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Garden CropsAvocados, growing
Beet leafhopper, curly top virus outlook
Blossom end rot, tomatoes
Cucumbers turn yellow
Curly top virus
Curly top virus and mustard weeds
Early tomatoes need protection
Freeze damage, chile
Freeze damaged fruit – edible?
Frozen tomatoes - edible?
Grape propagation
Growing fig plant from fruit
Melons in small space garden
Old garden seeds
Pineapple question
Rakkyo onions
Rhubarb, fertilizing
Saving vegetables from first frost
Squash dies even in light frost
Squash plant leaves turned black
Spider mites on avocado
Sweet corn varieties
Tomato blossoms drop
Tomato curl-top virus
Tomato, chile plants too tall?
Tomato plant is twisted
Tomato tree?
Tomatoes have aphids
Tomatoes not fruiting
Tomatoes, tips for good-eating
Vegetable planting, how early?
Watermelons with cucumber flavor?
Watermelons, when to pick?
When to plant in northern New Mexico
Blossom end rot in container tomato 5-00
Q. I’m growing several tomato varieties in containers and am having trouble with blossom end rot. I water every morning and by evening they are completely dry. I also fertilize every 2 weeks. I have bark mulch. What am I doing wrong?
A. The problem is probably that the containers are too small. This is evidenced by the fact that by evening they are completely dry. You didn't indicate anything about the potting soil that you are using. The potting soil could be a minor source of the problem if it is deficient in calcium. However, your water should supply sufficient calcium unless you are watering with distilled water.
Blossom end rot is caused by a deficiency of calcium at the blossom end of the small fruit as it begins to form. The calcium is part of the "glue" that glues cells together. A deficiency of calcium will appear as blossom end rot when the affected area begin to breakdown as the fruit enlarges. Once the blossom end rot appears, there is no solution for that fruit. In New Mexico, calcium deficiency in the soil is not a problem, except perhaps in potting soil, but that is usually remedied by the calcium in our water. Here in our dry state, the problem occurs when the calcium fails to reach the end of small developing fruit because of drought stress. The calcium travels through the plant dissolved in water.
On days when the plants wilt, there is often insufficient water to carry the necessary calcium to the end of the new fruit. Then, though damage has been done, the symptoms do not appear for a few weeks until it appears in the enlarging fruit. The solution is to prevent the wilting of the plants. In your case, moving the tomatoes to a larger container with a greater volume of soil, and thus a greater reservoir of water, may help. Another solution is to water the plants during the middle of the day. Finally, and probably a good idea in combination with either of the previous answers, is to place the containers and the plants in a place that is sunny in the mornings but shady in the afternoons.
Another good idea is to use light-colored pots for containers, or place something between the sun and the pot so that the pot is shaded. This will reduce the heating of the soil in the pot, reducing evaporation and damage to tender roots in the soil.
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Cucumbers turn yellow 9-01
Q. My cucumbers are an exotic but frightening yellow color. What has happened?
A. I discussed your question with Dr. George Dickerson, NMSU Extension Horticulture Specialist, who works with home vegetable crops. He thinks that you have planted "lemon cucumber," a cucumber that is yellow in color and is usually not as long as regular cucumbers. Another suggestion is that the cucumber is ripening. That is, the seed inside are maturing and getting hard and the color of the fruit is changing to indicate maturity.
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Curly top virus and mustard weeds
Q. I hear people saying that there will be a problem with a virus in our gardens this year because of the mustard. What does this mean? How can mustard cause problems in the garden?
A. There are several winter annual weeds in the mustard family that are growing very well this year because of the moisture in most New Mexico soils. One of these, London Rocket, is known to allow the curly top virus to overwinter and then infect our garden crops in the spring (especially tomatoes and chiles). There are other plants known to allow overwintering of the virus, but the mustard weeds also provide food and harborage to insects (beet leafhoppers) that spread the disease to our garden crops. The mustard plants flower in the late winter and early spring and then die. When they die, beet leafhoppers that were feeding on them move to other plants for food, and in the process they carry the virus to other plants. The virus does little to harm the mustard, but it causes severe problems with tomatoes and chiles.
It is important to realize that this virus cannot survive in the soil. It must remain in a living host. London Rocket begins germinating in the fall when it is possible for insects to carry the disease from garden crops to the mustard. The mustard sustains the virus through the winter and allows its return to the garden crops.
The curly top virus cannot remain alive in the soil, and unlike some bacterial and fungal diseases, it cannot reinfect plants grown in the same soils as plants that were infected last year. Curly top virus will not reinfect a garden through the use of compost made from plants infected with curly top last year.
The mustard weeds are prospering now. In many parts of the state, they are flowering and preparing to form their seeds (to germinate this fall and cause problems next year). The best method to manage curly top virus is to manage the weeds, not to attempt to control the insects that later spread the disease. Removal of mustard weeds from the vicinity of your garden now (before the tomatoes and chiles are planted) helps minimize the problem. In some situations, it is not possible to remove all mustard weeds; however, by increasing the distance from the weeds to the garden, problems may be minimized.
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Early Tomatoes Need Protection
Q. I planted some tomatoes early and on cold nights I covered them with clear plastic. One day I noticed that the leaves at the top of the plant had turned black. What happened? The rest of the plant looked okay.
A. It is very likely that it got cold enough to damage the plants only where the leaves touched the plastic. The plastic works by forming a film of water on its under surface. This film of water reflects the infrared (heat) energy being radiated from the soil so it is not lost to the atmosphere. Those leaves touching the plastic were less protected and were exposed to the temperatures experienced by the upper surface of the plastic, which probably fell below freeing. The lower parts of the plants were in the air kept warmer by the heat retained by the film of water.
The plant should not be severely injured by this. If the tip of the plant (the growing point) was injured, then new growth will need to develop from a bud lower on the plant. That will slow growth a little but should not result in permanent injury to the plant.
Try to use some material to keep the upper leaves from being in contact with the plastic, especially on cold nights.
Another possibility is that you removed the plastic a little too late one morning and the leaves were sunburned. However, it is more likely in that situation that the heat would accumulate under the plastic and the whole plant would be injured.
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Freeze damage to chile plant 12-00
Q. We have a chile as a houseplant. The top ¾’s of it got frost-bitten when we briefly placed it outside. Should we prune these apparently dead branches now or wait so see if the leaves will come back?
A. The chile plant may be able to regrow after this injury. It depends on how much damage was done by the cold weather. Since it was outside briefly, and if the temperature was not too cold, there is an excellent chance that only the ends of the branches or perhaps only the leaves were injured. It would be a good idea to wait and see if regrowth occurs. During this time, reduce watering. The fewer leaves the plant has remaining, the less water it will use. If you continue to water normally, there is a chance of causing root rot. As new leaves are formed, begin increasing irrigation frequency. It is good to know that someone else likes to grow chile as a houseplant. Many people think that it is an annual and only lives for the summer. The fact is that it functions as an annual because it freezes outside. In warm climates, or when it is grown indoors, it can live for several years.
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Freeze damaged fruit
Q. My tomato plants froze pretty severely a couple of nights ago. I just pulled them up and threw them away. A friend told me I could have saved the tomato fruit and eaten them. Is that right? I thought they were ruined by being frozen.
A. If the fruit were not frozen and after a couple of days had shown no symptoms of injury, they could have been harvested and eaten. However, if they were injured by frost, then disposal is the appropriate treatment. According to Patricia Aaron, Home Economist for the Bernalillo County Extension Service, it is best to err on the side of caution. Any fruit damaged by freezing begins to decompose, or rot, rapidly as it thaws. Since there are fungi and other decomposing organisms which produce chemical toxic to humans and pets, if the fruit was damaged, it should be discarded. According to Patricia, many people take unnecessary risks with unsafe food. They think they can just cut off the affected part of the fruit, and then it is okay. She points out that a fungus can extend further into the fruit than the damage. Though we may not see the fungus, it may penetrate far into the fruit. If the fungus produces a toxin, then by only cutting out the damage they see, these people ingest the poison endangering themselves, their family, and anyone who shares the meal with them.
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Frozen Tomatoes - Are they edible?
Q. My tomato plants froze the other night so I went out the next morning and picked all the green tomatoes. Will they ripen in my kitchen? Some are turning very soft and mushy, but they are still green. Is that okay?
A. The fact that they are turning mushy means that they froze. According to Patricia Aaron, Bernalillo County Extension Home Economist, once fresh fruits and vegetables have frozen and thawed decay begins quickly. They are not safe to eat. As with packaged frozen fruit and vegetables that have directions telling you not to re-freeze once thawed, the fresh fruits and vegetables should be used as soon as they thaw or should be discarded. Patricia said that most people are aware of this when it comes to protein foods like meat, milk, eggs and such, but the same principles hold true for fruits and vegetables.
If some of the tomatoes were not frozen, remain firm, and show no deterioration, you can allow them to ripen in the house or you can eat them as green tomatoes. Patricia has a publication with green tomato recipes available if you call the Bernalillo County Extension office at (505) 243-1386 and ask for the publication “Green Tomatoes.”
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Grape propagation
Q: What is the technique for propagating grapes from cuttings?
A: During the summer, grapes may be propagated using leafy cuttings. Stems of recently matured growth cut about 18 inches long may be rooted if they are treated with root-inducing growth regulators and kept under high humidity. High humidity is a problem in New Mexico unless you build a propagation bed with a mist system to frequently moisten the cuttings. Use of the process called layering will probably be more successful and may also be done in the summer. In this method of propagating the vines, the cutting is induced to form roots before it is severed from the parent plant. The vine must be bent to the ground. This vine should then be wounded by cutting it slightly, girdling it, or wrapping wire tightly around the stem. Treat the wounded area with root-inducing chemicals and bury the wound in good garden soil or potting soil. After several weeks, roots will form. Next spring, just before growth begins, this rooted vine may be severed from the parent plant and moved to its permanent location. Another form of cutting that is successful may be accomplished in the late winter with dormant vines. Vines about one-half inch in diameter and one to one and one-half feet long are severed from the plant. The basal portion of the vine should be treated with root-inducing chemicals. These cuttings should then be placed in good potting soil or garden soil so that only one bud remains above the soil. Keep the vines well watered, and they should form roots as the leaves begin to develop. By the end of the summer or the next spring before growth begins, the vines may be transplanted to their permanent location in the garden.
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Growing Avocados
Q. Can you help me on how to go about growing an avocado bush?
A. You didn't state where you wish to grow avocados. It is not hardy outside in any part of New Mexico. The avocado is a large tropical tree. It can, however, be grown indoors as an ornamental in a greenhouse or well-lighted atrium. It will be difficult to get large enough to produce fruit, and as you described may be best grown pruned as a shrub. I have grown avocado seeds by planting them in good potting soil and waiting. I used a sandy soil that did not hold too much water and therefore would not stay soggy.
To keep from forgetting to water the seeds, I planted some flowers in the pot. By keeping the flowers well watered, I didn't let the avocado seed dry. In one case it took over three months for the seed to germinate and grow. In other cases the seed germinates much more rapidly. I have also stuck tooth picks into the side of the avocado near the broad end and placed the toothpicks across the top of a narrow drinking glass filled with water so that the narrow end of the seed was in the water. In this case I could watch the root begin to grow and plant the seed in soil when the root appeared. Finally, I have just placed the seed into a small plastic drinking cup with just a small amount of water. I closed the top of the drinking cup with plastic wrap held with a rubber band around the top. When the root appeared, I planted the seed. In every case I have had some failures and some successes. It depends upon the maturity of the seed and keeping the seed from rotting while waiting for it to begin to grow.
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Growing fig plant from fruit 9-02
Q. Can you grow fig plants from the ripened fruit? I have a box of fresh Kadota figs and fresh brown Turkish [sic] figs and would like to start a tree from one or both of them.
A. Figs rarely make viable seeds. While I haven’t looked at Kadota, I have never seen a seed with Brown Turkey (Turkish) figs. The crunchy things inside the fig are usually aborted ovules that never matured into seeds. The structure of the fig inflorescence (flower structure) is unusual. The flowers are inside the "synconium" or enlarged stem base. It is this synconium that forms the fig fruit. In order for the fig to form viable seeds, a small wasp must enter the synconium from an opening at the end, lay her eggs inside the fruit, and in the process pollinate the small flowers that line the interior of the fruit. Most people don’t like the idea of eating the small (maggot-like) wasp larvae, so fig breeders have developed varieties of figs that do not require pollination and thus have no wasp larvae inside. Without pollination, no viable seeds are formed.
Figs are most often propagated by cuttings. This is a fairly easy process if you have access to small branches pruned from the fig trees. This can be done successfully in the spring or fall. As a child growing up near Houston, I had success rooting fig cuttings by placing them in the soil on the north side of my home. In arid climates, a greenhouse or some cover to increase humidity and reduce evaporation would be helpful.
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How does a pineapple grow?
Q. Does the pineapple fruit hang from the tree, or is it grown underground like a potato?
A. The pineapple plant is a monocot, meaning it is related to grasses and lilies. The fruit is produced at the top of a dense cluster of stiff leaves in the same manner that grass flowers are produced above grass leaves. Have you noticed the little "plant" on top of the pineapple fruit? This is a small version of the plant which produced the pineapple.
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Melons in small space gardens 5-01
Q. I live in a townhouse and have a very small patio, but I want to grow watermelons. The last time I tried to grow them, they spread all over the patio so that I couldn‘t use it. Are there some melons that won ‘t take over? Albuquerque, NM
A. There are some melons advertised to have compact vines. I don‘t know if they will be compact enough to solve your problem. However, if you combine them with the concept of using vertical garden space you should be able to grow melons if the location provides enough light. Plant the melons along a strong trellis or wire fence and encourage the melons to climb this supporting structure. This will keep them from sprawling across the patio. Then the next concern, the weight of the melons, must be addressed. You will need to support the melons on the trellis to keep them from breaking and falling from the vine under their own weight. To do this, form a sling from old t-shirt or old panty hose material. Tie the ends of the sling to the trellis and support the melon in the sling. Be certain that the sling surrounds the melon enough to prevent it from falling out when the wind blows (plan on strong winds). If you choose one of the varieties of smaller icebox melons, you should have no problem growing your own tasty melons. This will also work for cantaloupe and small pumpkins. You will also benefit from some additional shade on the patio - just don‘t sit under a suspended melon. If the sling fails, that could be a dangerous location.
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Old garden seeds 4-02
Q. I found some old seeds and wonder if I can plant them with any expectation that they will grow. They are tomato, chile, and bean seeds that I saved from my garden several years ago.
A. These vegetable seeds may have survived a few years if they did not get too hot during storage. High humidity (not much of a problem here in New Mexico) and high temperatures can greatly reduce the ability of seeds to germinate. Storage at low humidity in a refrigerator is the best possible condition. You can take a few of each type of seed you have saved, roll them in moistened blotter paper or a paper towel, and store them in a sealed plastic bag. After a few days to a week or so, you can unroll and count the germinated seeds to determine the percentage of live seeds. If you have no germination under these conditions, you will probably have no success in the garden.
Another consideration is whether or not the plants from which you collected the seeds were hybrid or open-pollinated varieties. Hybrid vegetable seeds are common because they tend to produce more vigorous plants and greater yields; however, there are also many open-pollinated varieties available. Seeds saved from hybrid plants will not retain the hybrid vigor of their parents and will not produce fruit of the same quality. If the original plants were hybrids, you may be disappointed with the results. If you have enough room in your garden, you may find it interesting to see what results. If the plants were open-pollinated varieties, this is not as great a concern.
However, open-pollinated varieties may have been pollinated by another variety grown nearby. This could result in new plants that don’t produce the expected fruit. Bell peppers grown near hot chile may have received pollen from the hotter chiles, so the fruit may not be shaped like a bell pepper and may be hotter than you expected if you grow them from these seed.
So, the answer to your questions is that if the seeds are still viable, the results may not be what you expect. You can certainly plant them if you wish, but to have a more dependable yield you might want to plant new seeds from known hybrid or open-pollinated varieties.
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Rakkyo onions
Q. My mother would like your recommendation for a fertilizer for a white bunching onion (a Japanese Allium species called Rakkyo), something like a cross between a shallot and a garlic. We plant it in boxes and have gotten good crops just using some steer manure, but we were wondering what you would recommend for the development of large bulbs. Also, what time of year should we plant it and when should we harvest it? One year we waited until flower stalks had formed. This year Mom insisted on harvesting the bulbs right away (a few days ago) and says we should re-plant the large bulbs in about a week. I thought we should wait until the leaves turned yellow.
A. Although New Mexico is an important commercial producer of large-bulb onions, bunching onions are a good choice for home gardeners. These onions do not produce large bulbs but are useful because you can harvest a few "green" onions (small bulbs and leaves) as you need them while they are growing. You may also harvest only a few leaves for flavoring a salad, soup, or other dish. This makes them very convenient for the kitchen gardener.
Store-bought green onions are often large-bulb onions harvested before the bulb enlarged. Rakkyo onions will not produce the large bulbs. It is sometimes called Japanese chives. Unlike true chives, the bulb will enlarge somewhat (to shallot size) but will not reach the size of the large bulb onions you purchase in the grocery store. If you want to grow large-bulb onions, you should purchase the onion sets (transplants) that will produce the larger bulbs. Grow them in addition to the bunching onions. You described the Rakkyo as a cross between a shallot (mild flavored onion) and garlic. Its flavor is unique. There are other shallots, chives, and bunching onions to add to the kitchen garden collection along with the large-bulb onions. Each type will have its distinct flavor and contribution to culinary art in the kitchen.
You can leave the bunching onions in the ground while they are dormant in the summer, or you can dig them and store them to replant as the weather begins to cool (August or later). The small bulbs of the bunching onions will best survive storage if you wait until the foliage yellows before digging them. If you dug them while still green, plant them more quickly. However, you have probably waited long enough if you just dug the bulbs recently. The leaves should stay attached until they dry, and then you can remove them.
Research at New Mexico State University has shown that the primary fertilizer nutrients needed by onions in New Mexico are nitrogen (which the steer manure provides) and phosphate. Our soils have high levels of phosphorous, but it is often not available to plants because of the high calcium content or our soils. To best determine how to fertilize your onions, have your soil tested. You can get soil testing information from your local Cooperative Extension Service office. Tell the testing laboratory what crop you plan to grow.
Research has also shown that crop rotation is important when growing onions. It is best if onions are not grown in the same soil more often than once every 5 years. Since you are growing the plants in boxes and to prevent accumulation of disease organisms in the soil, change the soil in the box every year, if possible. You can also grow many types of onions in native New Mexico soil after preparing the soil according to directions from the soil testing laboratory (unless you live in an apartment and have no space to garden except in pots and boxes).
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Saving vegetables from first frost
Q. I hope this isn't too late. For several years when the first frost arrived, my tomatoes plants were loaded with fruit. After frost, I just threw them into the compost. Is it possible to save these vegetables?
A. I usually get more questions than I can answer in this column and choose one or two to answer; your question gets moved to the head of the line. This is a very relevant question for right now. While some parts of New Mexico may have already had a frost, most inhabited parts of the state have not yet suffered the end of the garden season. Warm season plants such as tomatoes, chiles, beans, squash, and others stop producing new fruit when the nights start getting cold, but there is still ripening fruit on the plant. To preserve this fruit until it is ready for harvest, you can employ several techniques. Yes, I am calling these vegetables fruits because the portion of these plants we harvest to eat is the part of the plant which produces the seeds. Botanically that is the definition of the fruit, even though when we eat it we consider it a vegetable, a culinary distinction. If the fruit freezes, it should be discarded.
Our purpose will be to prevent it from freezing. You can cover the sensitive plants with old bed sheets, blankets, or other opaque material in the evenings before a frost is expected. In fact, a heavy covering of leaves on the plants may protect the fruit as well. Whether covered by the leaves of the plants or your blankets, the purpose is to hold heat radiated from the soil around the fruit and prevent frost. The upper surface of the leaves or blanket may be covered with frost in the morning, but the heat held under the leaves or blanket prevents damage to the fruit. If a hard freeze is predicted, these coverings may not be sufficient. In the case of a "hard freeze," lower temperatures and, often, convective heat loss are expected. Covering may work if the freeze is not severe, or if one or more light bulbs are placed under the covering with the plants to generate heat. However, it may be necessary to harvest the fruit and allow it to finish ripening indoors. At least there is no hazard of electrocution this way.
Tomatoes which are full size and have already begun to show a lighter green color should ripen indoors. Some people uproot the plant and hang it from the rafters of a garage or basement. Whether individual tomatoes or tomatoes on hanging plants, you should have tomatoes ripening over a period of a few weeks. One year many years ago, I harvested over fifty green tomatoes and stored them on the kitchen counter. We ate red tomatoes until Christmas. By then, however, those ripening were not very flavorful and we had a cluttered kitchen for longer than my wife could tolerate. The smaller tomatoes which have not begun to lighten in color can be eaten as fried green tomatoes or preserved as green tomato chow-chow or as other types of tomato preserves. Directions for preparing these tomato products are available from your local Cooperative Extension Office and on the internet. Check the New Mexico State University, College of Agriculture and Home Economics World Wide Web home page for this and more information (http://www.cahe.nmsu.edu/cahe).
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Squash dies even in light frost
Q. Some of the leaves on my squash plant turned black this morning. Last night the temperature dropped to the mid-thirties, but it didn't freeze. I have a recording thermometer and checked. Did my squash get a disease last night? Will it spread? Is it okay to compost the plants?
A. The leaves were blackened by a light frost. Even though the thermometer didn't record a freezing temperature at its location, the location of the plants in the garden was probably just at freezing. We tend to put our thermometers at eye level, several feet above the level of plants in the garden. On a calm night, temperatures at the surface of the leaves can be several degrees colder than at thermometer level. Leaves which were injured by frost will blacken as they are heated by the sun in the morning. Upper surfaces of leaves that are exposed to the night sky will be most subject to radiative cooling and will be the ones injured. Leaves covered by other leaves will retain a little more heat and not suffer the frost damage. You didn't notice the frost itself because it was spotty and quickly dissipated as the sun rose. So, your plants didn't get a disease for you to worry about.
The plants may, and should, be composted. If only a few leaves were injured, the plants may continue to grow and mature fruit for another week or several weeks until another cold night freezes or allows a more extensive frost. Fruit, squashes on the plant which were protected from radiative cooling, may still be left on the plant. Any fruit that shows damage due to the frost should be discarded. Be sure to harvest any mature squash before the next cold spell.
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Squash plant leaves turned black!
Q. Some of the leaves on my squash plant turned black this morning. Last night the temperature dropped to the mid-thirties, but it didn't freeze. I have a recording thermometer and checked. Did my squash get a disease last night? Will it spread? Is it okay to compost the plants?
A. The leaves were blackened by a light frost. Even though the thermometer didn't record a freezing temperature at its location, the location of the plants in the garden was probably just at freezing. We tend to put our thermometers at eye level, several feet above the level of plants in the garden. On a calm night, temperatures at the surface of the leaves can be several degrees colder than at thermometer level. Leaves which were injured by frost will blacken as they are heated by the sun in the morning. Upper surfaces of leaves that are exposed to the night sky will be most subject to radiative cooling and will be the ones injured. Leaves covered by other leaves will retain a little more heat and not suffer the frost damage.
You didn't notice the frost itself because it was spotty and quickly dissipated as the sun rose. So, your plants didn't get a disease for you to worry about. The plants may, and should, be composted. If only a few leaves were injured, the plants may continue to grow and mature fruit for another week or several weeks until another cold night freezes or allows a more extensive frost. Fruit, squashes on the plant which were protected from radiative cooling, may still be left on the plant. Any fruit that shows damage due to the frost should be discarded. Be sure to harvest any mature squash before the next cold spell.
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Spider mites on avocado 10-00
Q. I have a 12-year-old avocado tree. It has spider mites. What is the best way to get rid of them? I’ve been battling them for about 6 years.
A. In our climate, an avocado is an indoor plant, so it will be important to use pest management practices that are useful indoors. If your tree is in an area with a tile or concrete floor (a floor that will not be damaged by water), spraying frequently with water may be sufficient to keep the mites from doing damage. They will survive, but their populations will remain low enough to be non-damaging. Smaller plants may be moved outdoors when the weather allows so that they may be sprayed with water. Larger plants on platforms with casters may also be moved outdoors and sprayed.
The benefit of using water is the non-toxicity of the water to the person doing the application and the lack of potential damage to the plant. Insecticidal soap should also be useful. It may be damaging to some plants (read the label for warnings), and some people are allergic to the soap. Soap may also be damaging to carpets, curtains and upholstery, so the plants must be in an area without furnishings which may be injured when the insecticidal soap is applied. Use of water sprays or insecticidal soap on a frequent basis should keep the spider mites at bay; however, if the infestation is too severe, you may choose to apply a miticide labeled for use on ornamental plants. Such products must be applied out of doors when the weather permits. Read and follow all label directions.
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Sweet corn varieties 4-02
Q. I lost my notes from an Extension Service presentation last year. In that talk Dr. Dickerson told about different sweet corn varieties, including some that are super sweet. How can I tell what varieties are sweetest?
A. It is time to begin planning for planting corn in New Mexico, and it is wise to consider which variety you want to plant. Dr. George Dickerson, NMSU Extension Horticulture Specialist, tells us in NMSU
Extension Guide H-223, "Home and Market Garden Sweet Corn Production," states that there are several varieties of sweet corn with more sugar than the older varieties. These are based on different genes in the corn. The gene for sweetness in the old sweet corn varieties was called the "su-1" gene. Sweeter varieties of sweet corn contain the "sugary enhanced" gene, "se". These are roughly twice as sweet as standard sweet corn and the sugar is more slowly converted to starch than in standard varieties. This means the sugary enhanced sweet corns start sweeter and remain sweeter longer.
Another genetic variation occurs in varieties with the "sh2" gene. The sh2, or super sweet varieties are three to four times sweeter than the standard sweet corn varieties. The "sh2" means the corn kernels are shrunken (shriveled). This is obvious when looking at the seed. In the sh2 varieties, the enzyme that converts sugar to starch is also reduced, so the corn remains sweet much longer. These varieties are more sensitive to soil temperature and should only be planted when soil temperatures are above 55 degrees, and they should be planted only half as deep in the soil. They are also more influenced by pollen from other corn varieties. Pollination by other corn varieties, including sweet corn varieties, can result in starchy, rather than super sweet corn kernels.
If you wish to plant several varieties in the same garden and can’t provide 250 to 300 feet separation between them, then plant them two weeks apart so that one variety will not pollinate the other variety. This is most important for the super sweet varieties.
Some people complain about the texture and taste of the super sweet varieties. They lack the creamy texture of the standard and sugary enhanced varieties because they contain a lesser quantity of water-soluble polysaccharides (complex sugars). They also have a tougher pericarp (outer covering) that gives them a more "crispy" texture. Unlike the super sweet varieties, the sugary enhanced varieties have the same texture as standard sweet corn varieties.
If you are growing sweet corn for your own use, you can choose varieties based on texture and sweetness. If you are growing for the market or to give to friends, you should probably give more consideration to the difference in sweetness. The super sweet varieties will remain sweet much longer. Also consider the fact that the varieties containing more sugar in the seed will be more susceptible to disease organisms when germinating. For more information, you can find Dr. Dickerson’s publication at the NMSU College of Agriculture horticultural publications web site at http://www.cahe.nmsu.edu/pubs/_h.
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Tips for good-eating tomatoes
Q. I am looking for a large, good-eating tomato to plant this year. In the past I have had good luck with tomatoes, but they are not as large as I would like. This is for a home garden. Please send me the name of a tomato I described.
A. Answer courtesy of Dr. George Dickerson, NMSU Extension Horticulture Specialist: Try Burpee's Super Steak Hybrid VFN tomato. This 80-day-rated tomato is not only large in size, it has excellent flavor and good disease resistance (VFN). You may also want to consider Beefmaster VFN, another 80-day-rated tomato. The 80-day-rating means that it should be producing ripe tomatoes approximately 80 days after transplanting into the garden. Here in New Mexico that often occurs during the time that our temperatures have become hot. Some tomatoes, especially those which produce larger fruits, cease production when the temperatures climb. You may want to plant some of the smaller fruited tomatoes to maintain production through the heat. The cherry tomato types seem to continue bearing tomatoes regardless of temperature conditions.
Dr. Dickerson has gathered information on tomatoes in New Mexico by growing them himself and by sending questionnaires to Master Gardeners and other gardeners around New Mexico. The tomatoes recommended above and others are listed in the publication, "Growing Zones, Recommended Crop Varieties, and Planting and Harvesting Information for Home Vegetable Gardens in New Mexico" (Circular 457-B). This publication is available from your local Cooperative Extension Service office. There is a Cooperative Extension Service office in each county in New Mexico. Yours is in Roswell. If you have a computer, you can also find this publication on the World Wide Web at http://www.cahe.nmsu.edu/cahe/redtops/ which gives you access to many other New Mexico State University Cooperative Extension Service publications.
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Tomato blossoms drop 5-00
Q. I wanted to get a fast start on producing tomatoes, so I bought large plants with flowers on them. As soon as I planted them in the garden, the flowers began falling and no tomatoes have formed. What is wrong? It has been two weeks and I still don't have any little tomatoes.
A. The problem is that the tomato plants were moved from the nursery where there was probably more shade and protection from the wind. Now they are in the sun and more exposed to our winds. The plants must now adapt to the different soil conditions and extend their roots from the nice, rich, potting soil into the New Mexico soil of your garden. In other words, your tomato plants are suffering some transplant shock. In another week or so, as the plants become established and begin growing, they should also begin to set fruit. Some varieties, especially the larger fruited varieties of tomatoes, take longer than others so it may take even longer. If it takes too long, then your plants will run into temperature problems. Once the days become too hot, the tomato plants will stop setting fruit (or fail to begin) until the temperatures begin to decline. This usually occurs with the arrival of our monsoon season. (I do hope the monsoon rains and cooler weather do arrive in New Mexico this year!) For now, continue to keep the soil around the plants moist, not soggy, and wait until the plants have established in their new location.
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Tomato, chile plants too tall? 6-00
Q. When I bought tomato and chile plants for my garden, the only ones left in the nursery were tall. Are these plants okay? Can I plant them deep?
A. Tomatoes are capable of producing new roots along their stems, so tall, leggy plants may be planted deeply and allowed to form roots along the stem. Because of this characteristic of the tomato plant, this is often done by New Mexico gardeners to help the plants develop a more extensive root system and to develop a deep root system that helps the plants avoid drought. Tall tomato plants are okay to plant and can indeed be planted deeply. Other plants, such a chiles and peppers, don't have the same ability to root along the stems and don't accept this type of planting as readily. They may be planted somewhat deep but not as deeply as the tomatoes.
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Tomato curl-top virus 7-99
Q. The leaves on my tomato plants are turning yellow, and the plants seem to be dying. This started on one plant but has now spread to the neighboring plants. What can I do to save the rest of my tomato plants?
A. There are several diseases killing tomato plants in New Mexico this year. Some diseases are viral and others are fungal. In both cases, you should remove diseased plants. I spoke to Dr. Natalie Goldberg, NMSU Extension Plant Pathologist, who thinks you have described curly-top virus symptoms. She is getting reports of extensive curly-top problems from many parts of New Mexico. In this case, removal of infected plants is especially important. Curly-top virus is spread from plant to plant by small beet leafhopper insects. After they feed on an infected plant, they carry the virus to each subsequent plant on which they feed. Insect control is not effective in preventing the spread of the curly-top; removal of infected plants is more effective if the plants are removed before the leafhoppers can spread the disease.
Because curly-top is not soil-borne (spread through soil), it is possible to replant tomatoes this year or next year at the same site. For this reason, you may also compost the infected plants as long as there were no fungal diseases involved. The compost cannot spread the curly-top virus to the plants next year. From your description, we diagnosed virus; however, Dr. Goldberg and I also discussed the possibility of fungal disease as well. In this case there would be spotting of the leaves, wilting, and other symptoms. The yellowing of the leaves would probably begin at the base of the plant and progress upward with black spots developing on the leaves. If these symptoms are present, you may have fungal disease in your tomatoes. Removal of the infected plants is still recommended, but some of the other information above changes.
If your plants have fungal disease, it is unwise to plant tomatoes, or related plants such as chile and eggplant, in the same site this year or for the next couple of years. Fungi can be soil-borne and spread from the soil to the plant. Composting plants infected with fungi can also be a way of spreading the disease. If your compost gets hot enough, or if you treat the diseased plants to high heat before composting, you may avoid problems, but be careful. If you wish to compost plants which may have fungal diseases, you may solarize the plants to kill the fungi. Do this by sealing the infected plants in a black garbage bag which is then placed in sunlight. Allow them to remain in the sun for several days. As the plants in the bag are heated, the fungi will be killed. Of course, the plants are dead, but they may now be composted. This is a good practice for any plant you think may be diseased when you aren't sure and don't know what disease is present. Rotating your crops to different locations in the garden each year is also a good practice to avoid the buildup of diseases in the soil.
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Curly Top Virus 3-03
Q. What is curly top virus and is there a cure for it? I have received about 15 different varieties of heirloom tomatoes, and I do not want to expose them to this virus.
A. Curly top virus is a plant disease that affects many garden crops, especially tomatoes and chile. While this virus is harmful to plants, it does not harm people, so the concern is exclusively for our plants.
The virus cannot overwinter in the soil; it must remain in a living plant. Plants cannot be infected by planting them in soil where infected plants grew last year or by use of compost from infected plants. Infection involves transfer of the virus from plant to plant by insects. Some perennial weeds, some landscape ornamentals, and especially the London rocket (mustard weed) carry the virus through the winter. The most common method of disease transmission is by an insect called the beet leafhopper. As the insect feeds on the weeds, it takes in some of the virus. When the insect feeds on a tomato or chile (after picking up the virus), it may then transmit it to the vegetable.
Symptoms of curly top include yellowing of the new growth, curling or twisting of the leaves, and often development of a purplish cast on the mid-rib on the underside of the tomato leaf. Perhaps the least desirable symptom is that crop yield is greatly reduced.
There is no cure, only prevention. Good weed management during the spring is essential. Removal of weeds that carry the disease should be accomplished before the susceptible vegetables are planted. Insect control is not effective. Treatment with insecticides will usually not stop spread of the disease. Row cover fabric surrounding tomatoes and chiles will provide protection from the spread of curly top virus. This may be a reasonable solution for limited numbers of plants. The row cover material will also provide some wind and sunscreen protection.
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Tomato plants not forming fruit 8-01
Q. I have just moved to the East Mountains from Illinois and need some help growing tomatoes here. I brought tomato plants with me from Illinois, and they look like the healthiest plants I have ever grown. They are in tomato cages, and I have not pinched off side sprouts. In Illinois, by this time I should be having ripe tomatoes, but here there is not a single tomato set on the five plants, and very few blooms. One person suggested that tomatoes won’t set because it gets too cool in the nights here. I would greatly appreciate any help you can give me.
A. There is probably more than one factor working here. First, our summer day temperatures kill the tomato pollen, so even when the plants are flowering, there is little to no fruit set. This is variety dependent - cherry tomatoes, saladette, and other smaller varieties usually set better at high temperatures and often have a crop set before high temperatures develop. The varieties that produce larger fruit have more difficulty. Low night temperatures can reduce flower development. Your statement that these were the best plants you have ever grown indicates good growth and perhaps high nitrogen fertilization (from commercial fertilizer, manure, and some composts). Nitrogen coupled with low night temperatures may reduce flower development, and high day temperatures may prevent flower set. Growing several different varieties (of different size tomatoes) gives you a better chance of having fruit set. Don’t make the soil too rich, nitrogen is needed, but balance with phosphate fertilizer. Choose varieties that will produce a lot of leaves. (Temperatures will be warmer under the foliage at night and cooler in the day time).
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Tomato Tree?
Q. Someone told me about a tomato tree. Is there such a tree as this?
A. The tomato tree or tree tomato is a plant in the tomato family but is not a tomato. Its scientific name is Cyphomandra betacea. The genus Cyphomandra includes about 29 other species, but only the species C. betacea is commonly grown for its fruit. The tomato tree requires warm temperatures since it is from the tropics. It is native to Peru. Outside the tropics, it must be grown in a greenhouse. It takes one and one-half to two years to become large enough to produce fruit. It needs a deep, fertile soil. However, I have seen it growing in a large pot in a greenhouse. In a pot, it might not reach its maximum potential size of over 10 feet. The fruit is orange-red, egg shaped, and about two inches long. The fruit may be eaten uncooked but is most commonly stewed or made into jelly. My reference did not describe its flavor. I have noticed that the plant has an unpleasant odor when you bruise or break the leaves and stems. Many plants in the Solanaceae, or tomato family, contain poisons in the parts of the plant which are not eaten. So, if you decide to grow the plant, eat only the fruit. I found no information about poisons, but caution is wise.
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Tomatoes with aphids 7-00
Q. Can you please help me get rid of the bugs on my tomatoes? I think they are aphids, but I’m not sure. I’ve tried using liquid Sevin® but it doesn’t seem to help. They have already killed one plant and are on several more. Your help is desperately needed. Julie
A. If the insects infesting your tomatoes are indeed aphids, very often the only necessary treatment will be to wash the insects from the plant with a strong jet of water. If the water is too forceful in a stream, it may do damage to plants, fruit, or flowers. A strong, fine mist or a strong, but not too intense, stream of water should suffice to knock many of the aphids from the plant. It will be necessary to repeat this treatment every few days. While the aphids are on the ground and while they are climbing back into position, they are doing no harm. However, even when they are not harming the plants, they are attracting predators which eat aphids. There are many such predators, so this can be an effective means of control.
If it is necessary to use insecticides, there are many labeled for control of aphids. It would be wise to take a sample of the insects to your local Cooperative Extension Service Office or to a good nursery to have the insects positively identified. Be certain you choose an insecticide product labeled for this pest and labeled for use on vegetable crops. There is also a harvest interval listed on the label. That is the number of days you must wait following treatment to harvest the vegetables. Read and follow all the label directions. The Sevin® you mentioned may have killed some of the aphids, but they reproduce so rapidly that it may seem to have failed. This will be true of other insecticides as well, so repeat applications may be needed. Harvest all ripe and nearly ripe fruit before each treatment, then wait the required harvest interval before harvesting again and treating again. Since the insecticide will probably kill the beneficial insects that eat aphids, once you begin treating it will be necessary to continue treating. The pest insects tend to return following treatments much faster than the beneficial insects. It is possible to mix treatments. If the infestation is extremely heavy as you seem to describe, use of insecticides first, then treatment by washing away insects in subsequent recurrences may be sufficient to control the problem. Remember to get a positive identification before beginning treatments as this will make it possible for you to achieve maximum success.
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Twisted stem on tomato plant 6-01
Q. One tomato plant stem is just laying on the ground all flat and twisted. What is wrong?
A. I discussed your question with Dr. George Dickerson, NMSU Extension Horticulture Specialist (vegetable and small fruit crops). I had considered curly top virus as a cause of your problems, but Dr. Dickerson didn’t think you would see that much twisting from curly top. He asked about fertilization. He specifically asked if a weed and feed fertilizer was accidentally used in the garden or in the lawn nearby. Some herbicides used in combination with fertilizer can cause very obvious curling and twisting of tomato (and other) plant stems and leaves. If accidental contamination by weed killer is likely, it may be best to remove the plant rather than hope it will manage to mature some fruits. This is because the herbicide is active inside the plant and may also be present in the tomato fruits. Watch for symptoms in other nearby vegetables. You would also be wise to contact your local Cooperative Extension Service office for more information. If herbicide is not the culprit, your Extension Service Agent should be able to help you diagnose the real problem.
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Vegetable planting, how early? 1-00
Q. The winter has been warm here in New Mexico. Does that mean I can plant my vegetable garden early this year?
A. The fact that the winter has been relatively warm thus far does not mean it will stay that way. Extremely cold, damaging weather has occurred in late winter and early spring in the past.
If you are anxious to plant early, watch the weather forecasts and consider using some of the devices designed to protect plants from cold weather. There are a number of effective devices available on the market, and home built devices are described in many gardening books. If you do choose to plant early, be prepared to replant later if the cold weather does develop late this year. Location in New Mexico determines how early you can try to get a jump on the season. Of course, southern New Mexico has the earliest opportunity for starting the garden and the northern and high elevation parts of our state require later starts, whether starting at the normal planting time or whether risking an early end to winter. It is fun to start early and to have early harvests, but there are definitely risks to consider when doing so.
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Watermelons with cucumber flavor?
Q. I have planted watermelons and cucumbers close together in my garden. Friends told me that was a mistake, that the watermelons would taste like cucumbers. Do I have to move my melons further from my cucumbers? If so, how far?
A. Your are in luck, you don't have to move your plants. There would be a problem only if you were planning to save seeds from your watermelon to plant next year. The effects of the pollen are expressed in the next generation, so if you saved seed and planted them next year, then the melon would have characteristics of the cucumber. Even then, the cucumber pollen would only have an effect if the genetic material from the cucumber pollen successfully fertilized an ovule forming a seed. With regard to the watermelons produced this year, the pollen from the cucumbers would not affect the flavor of the melons. The melon is produced by the mother (seed) plant; only the seed itself is affected by the genetic material in the pollen. Since we do not intentionally eat watermelon seeds, and they do not contribute significantly to the flavor of the melon, this year's crop should not be affected.
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Watermelons, when to pick?
Q. How can I tell when my watermelons are ready to harvest? Every year I waste several, picking them before they are ready or waiting so long they are overripe. Thumping them doesn't work for me.
A. Choosing a ripe watermelon is a challenge. In the field or garden it is much easier than in the store because you will have more clues. The indications to look for in the garden are the drying of the "pigtail" or tendril closest to the melon on the vine. If it dries while the leaves and rest of the vine looks good, the melon should be ripe. The tendril is not available to melon hunters at the grocery store. A second clue, which is available at the grocery, is the color of the "ground spot," the place where the melon rested on the soil. If this ground spot is yellow or a cream-yellow color, the melon is ripe. If it is green or white, it probably is not ripe. The rind at the soil spot should toughen and resist denting with a fingernail when the melon is ripe. Finally, for those with an ear for music or who can easily distinguish sounds, the ripe melon will have a dull thud when thumped, while the unripe melon will have a tighter, ringing or hollow sound. New Mexico State University Extension Guide H-216, "When to Harvest Vegetables" is available at your local county Extension office. This publication gives guidelines for determining when to harvest 40 common garden vegetables, including watermelons, cantaloupes, and pumpkins.
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How do I fertilize rhubarb? 3-03
Q. I would like to know the correct way to fertilize rhubarb. I have not been successful in the past.
A. When fertilizing rhubarb, it is important to consider the salt you are adding, as well as the salt already present in the soil. All fertilizers add salt. Rhubarb is native to soils that are moist, contain much organic matter, and little salt.
The part of the plant of interest to gardeners is the leaf petiole (the leaf blade is poisonous). Therefore, nitrogen (needed for leaf growth) is the most important nutrient to add when fertilizing. Other necessary minerals are probably present in the soil in sufficient quantities and do not need to be added, but they may be present in the fertilizer you will apply. A soil test can help you determine what nutrients should be added. Your local Cooperative Extension Service office can help you get your soil tested. Commercial fertilizers may be a good source of nitrogen if used carefully. Do not over-apply fertilizers.
Manure can also be used to supply the nitrogen, but be very cautious because manures common in New Mexico are high in salts.
For gardeners who are considering growing rhubarb in New Mexico, remember that it is not native to New Mexico. It is from moist regions of the world with constant soil moisture, well-drained soils, low salt concentrations in the soil, and high organic matter concentrations. These conditions are difficult to replicate in New Mexico. That doesn't mean we can't grow rhubarb here, only that we must modify the soil and frequently replant into newly prepared soil. Gardeners who successfully grow rhubarb in New Mexico also plant in shady, protected locations. Our sunlight and wind can cause leaf burn, reducing growth of rhubarb. Gardeners also recognize that in much of the state rhubarb will grow during the cool season and become dormant in mid-summer.
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Beet leafhopper, curly top virus outlook 4-03
Q. Do you have a "prediction" as to how the leafhopper population is this year regarding curly top virus in tomatoes? I have several tomato plants under water shelters and will be planting several more in the next week or so.
A. Extension Service agents around New Mexico report that there is quite a bit of mustard weed. These weeds serve as winter host to the virus and spring host to the beet leafhopper. They germinate in the fall and become infected with the curly top virus, then host the virus through the winter without being injured themselves. They also serve as shelter and food for the beet leafhopper that carries the virus from plant to plant. Therefore, the potential for curly top virus is fairly high in New Mexico this spring.
To minimize the problem, eliminate the mustard weeds. This will reduce the possibility of problems. You may also wish to wrap the tomato cages with cheesecloth or white row-cover fabric to exclude the leafhopper. Light and air can penetrate the covering, so the tomatoes grow well under the slight shade. You can unwrap the covering to harvest tomatoes and re-wrap it to continue the protection. If the tomatoes outgrow the cages and covering, then remove the covering. If the plants get the virus, you can still harvest any tomatoes that have formed.
It is important to remember that the curly top virus does not infect plants directly from the soil or from compost. For that reason, it is safe to compost curly top infected tomato plants and to plant tomatoes near areas of the garden that had curly top problems in previous years. Spraying insecticides to kill the leafhoppers provides little benefit. The insecticide often excites the insects causing them to spread the disease before dying. Weed management and preventing insect access to the plants are the best ways to reduce the potential for curly top virus problems.
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When should I plant my garden?
Q. I moved to New Mexico last fall and wonder when I should plant my garden. I noticed that the stores are selling tomato seedlings and other vegetable transplants, but a friend said it is too early. When is the correct time?
A. In New Mexico the correct time to plant varies greatly by location and from year-to-year. I called Carlos Valdez, the Extension Service County Agent for Los Alamos County, to ask when the last frost is expected in White Rock. He told me that the average last frost date is in mid-May in both Los Alamos and White Rock. However, when I asked him when he would plant tomatoes, he said that he would wait until the first of June. He also feels that this year may have a later cold spell than usual, but he also said that it is impossible to really predict. His feeling is based on the fact that it is quite cold now and some plants are budding later than usual.
In your area (White Rock) you can safely plant some of the plants that tolerate some cold weather. Lettuce, radish, kale, and other plants like these are more cold tolerant than tomatoes, beans, corn, and chiles. However, if you buy transplants at a nursery, harden them by gradual exposure to cold nights, wind, sun, and dry air. Plants from the nursery have been in a protected environment compared to the environment of your garden.
Gardeners in some other parts of the state have already planted their warm season vegetables. Las Cruces gardeners started several weeks ago. Albuquerque gardeners are planting them now. Santa Feans will soon plant their warm season gardens. Patrick Torres, Santa Fe County Ext
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