Solanaceous Crops
The Solanaceae family contains a number of economically important vegetables, including the potato, tomato, pepper, and eggplant. It also contains other crops like tobacco, ground cherries and garden huckleberries. The foliage as well as other parts of many of these crops contains highly toxic alkaloids, such as tomatine in tomatoes and solanin in potatoes. Potato tubers can turn green and become toxic if exposed to sufficient light.
Potatoes are occasionally listed as root crops, but the tubers are actually short, thickened underground stems. Plant certified seed potatoes from a nursery or seed catalog. Potatoes from a grocery store are often treated with a sprout inhibitor and may be more prone to disease.
Plant potatoes by cutting tubers into sections averaging 1 1/2-2 in., each containing at least one good eye or bud. Treat potato pieces with a fungicide to reduce chances of rot. When cutting tubers for planting, let the sections dry out in the shade for a day or two so that the cut surfaces of the sections or "seed pieces" develop cork or scar tissue. This reduces the chances of tuber rot after planting.
Plant potatoes in a trench 6-8 in. deep, spacing the seed pieces 12 in. apart. The soil beneath the trench should be well-conditioned with compost. Cover seed pieces with 1-2 in. of soil and compost, then irrigate. As foliage develops and plants reach 5-6 in. tall, backfill the trench with a mixture of soil and compost throughout the first part of the summer, hilling up the soil around the developing foliage. Keep at least three-quarters of the foliage above the soil line. Mulching the bed with straw keeps tubers cool. Tubers form on many stems rising above the seed piece and they must be kept cool. Seed pieces placed too close to the soil surface during hot weather form too much foliage and no tubers. Over-stimulation with nitrogen fertilizer can cause the same problem.
Potatoes can be harvested as new potatoes when the tubers reach a desired size. Skin on new potatoes slips easily from the tubers. Immediately use new potatoes because they have a short storage life.
As potato plants mature, growth slows and tops turn yellow and begin to fall over. Skin on the tubers becomes thicker, tougher, and more firmly attached. Dig potatoes carefully with a spading fork or shovel.
Store mature potatoes at 60¡F for two weeks, then lower storage temperatures to 38-40¡F. Do not let temperatures drop below this point or sugars will accumulate in the tubers, reducing their cooking quality and giving them a sweet flavor.
Tomatoes are the most popular vegetable planted in New Mexico home gardens, as well as across the United States. Tomatoes are easy to grow, but New Mexicans must make careful variety selections for their area. Tomato varieties come in various sizes, shapes, colors, and growth habits. Try growing several different varieties in the home garden.
Tomatoes are a warm-season vegetable and are sensitive to frosts. For early production, try raising plants to transplant into the garden, or buy transplants from local nurseries. Transplanting is recommended for the higher elevations of New Mexico where the growing season is short. To grow your own transplants, start them at least 8-10 weeks before planting them in the garden.
In central and southern New Mexico, tomatoes can be direct seeded. Plants may produce late, but they are generally more hardy and thrifty than transplants. Plant seed 1/2 in. deep in hills spaced 3 ft apart, or plant them in straight rows on the side of the irrigation bed. Thin tomatoes to one plant every 18-30 in. Leave the most vigorous plants behind when thinning.
In home gardens where space is a problem, many gardeners stake, cage, or trellis their tomatoes. Training tomatoes to stakes or cages keeps the fruit off the ground, reducing the amount of fruit rot that occurs on untrained tomato vines. Tomatoes that are staked and pruned usually produce fruit earlier; however, blossom-end rot and sunscald are more prevalent. Another disadvantage is that stake and cage systems require extra work and materials.
One-Stem Staking Method. Drive an 8-ft 252 stake at the base of the plant. As the tomato plant grows, pinch out any side branches that form in the leaf axils (fig. 2), allowing only the terminal to grow. Tie the plant to the 252 pole with soft cloth strips, string, plastic tape, or plastic-coated wire ties. Tie the plant loosely to avoid girdling the stem.
Two-Stem (or More) Staking Method. While the plant is growing,
allow more than one stem to develop, then remove any unwanted suckers,
leaving only the terminals to grow. Use wooden stakes or a trellis, or use
an overhead wire from which string or twine is tied loosely around the base
of the plant. Tie two or three strings per plant, depending on how many
branches you want. As the main terminals grow, untie the string from the
suspended wire, wrap it around the stem for support, and retie it once again
to the suspended wire.
Wire Cages. The major advantage of cages is that the unpruned vine provides foliage cover to protect tomatoes from sun scald or sunburn. By using cages, you avoid the tedious chores of tying and pruning. Gardeners can purchase several types of cages or make cages using concrete reinforcing wire or hog wire. Cage size may vary, but a cylinder 24 in. in diameter and 60 in. high is most common. Make sure the wire mesh is large enough so that you can reach in and harvest the fruit.
Not all tomato varieties adapt to staking and caging. Tomato growth habits are "determinate" or "indeterminate." A tomato with a determinate growth habit stops growing at a certain height because the main stem develops a flower bud and fruit at the top. Most determinate varieties are bushy, short, early bearing types, and most of the fruit matures at the same time. Determinate tomatoes are best left unstaked.
Indeterminate tomatoes grow and produce continuously throughout the growing season and do not terminate in a flower bud or fruit. Indeterminate plants are well-adapted to staking.
Tomatoes like an even supply of water throughout the season. Water tomatoes deeply to encourage deep root growth, soaking the soil at least 8 in. deep each time it is watered.
If tomatoes dry out, or if they are watered unevenly, many diseases may appear. Blossom-end rot is a physiological disease that appears as a leathery, sunken scar on the blossom end of the fruit. Mulching often helps reduce the disease by keeping a more even water supply available to the plants.
Tomatoes do not set fruit well when night temperatures are below 55¡F, or when daytime temperatures exceed 95¡F. When night temperatures are cool, it takes a long time for the pollen to germinate. The pistil or female part of the flower may have passed its receptive stage for fertilization, and blossoms may drop off. Earlier maturing varieties generally have better fruit set at lower temperatures, so experiment with different varieties. Additionally, hormones sold in nurseries and garden centers can be sprayed on the blossoms to help keep the female part of the flower receptive for a longer time. "Heat tolerant" varieties can be used in warmer areas of the state.
To ensure a good fruit set, many gardeners vibrate or shake plants at midday when temperatures are warm to scatter pollen for good pollination. Use a battery-powered toothbrush to gently shake each flower cluster, or if the tomatoes are staked or caged, hit the structure with a board or stick to scatter the pollen onto the receptive female portions of the flowers.
Buy or plant tomatoes that are disease resistant. Check with nursery staff where plants are bought, or check the seed label for the letters V, F, N, T, or A following the variety name.
"V" denotes resistance to verticillium wilt, a soil-borne fungal disease for which there is no cure. Symptoms of verticillium wilt first appear on the plant's older leaves, which turn yellow and dry up, often without wilting, and drop prematurely. The plant seldom dies, but leaf loss will cause tomatoes to sunburn on the plant.
"F" means the plant has resistance to fusarium wilt, another soil-borne fungal disease, of which there are two strains: races 1 and 2. Two Fs on the label indicate resistance to both races. Fusarium wilt is characterized by leaf-yellowing that progresses upward from the base of the plant. Leaves wilt noticeably before the plant dies.
"N" refers to nematode resistance. Nematodes are microscopic worms. The most important, root rot nematode, causes plants to form swellings or knots on the roots. Affected plants are generally stunted and may wilt in hot weather. Nematodes can be introduced by transplants set in the garden, then become persistent in the soil. Nematodes also occur naturally in some soils.
"T" refers to resistance to tobacco mosaic, a virus affecting tomatoes, eggplant, chile, and other related plants. Symptoms on tomatoes include light- and dark-green mottled foliage, with curling and slight malformation. The disease is easily spread, especially by people who smoke and handle plants without first washing their hands with soap and water. Merely brushing infected plants with clothing can spread the disease.
"A" refers to Alternaria resistance. Alternaria is a fungal disease of tomatoes often called early blight, alternaria stem canker, or black mold.
Many tomato varieties are resistant to three of the major diseases: verticillium wilt (V), fusarium wilt (F), and nematodes (N). Researchers continue to develop better disease-resistant varieties.
Beet curly top is a major virus disease of tomatoes in New Mexico. Spread by the beet leaf hopper, infected plants become stunted with stiff, curled leaves. Covering the plants early in the season with a row cover helps to prevent beet leafhoppers from infecting the plants and will help to reduce the incidence of this disease.
Peppers (Capsicum spp.) exhibit a wide variety of shapes, sizes, colors, and tastes. The term "pepper" should not be confused with "black pepper" (Piper nigrum), which is produced from the dried, unripe fruit of a vine grown in India and Ceylon. Peppers can generally be classified into two groups: mild- or sweet-tasting fruit (bell, pimento, sweet wax types) and fruit with hot or pungent flesh (long green and jalape?o types). In New Mexico, the latter are often referred to as "chile."
Direct seed peppers at about the average date of the last killing frost, or transplant them into the garden after danger of frost. There are several methods of direct seeding peppers. Many New Mexicans use the hill method, placing several seeds in hills spaced about 12 in. apart in a row. When seedlings appear, thin all but two or three of the stronger plants. Rather than thinning completely, allow some plants to continue developing for later transplanting to bare places where no seedlings sprouted.
As an alternative to the hill method, gardeners may choose to sow seeds in rows. Sow seeds about 1 in. apart in a straight row near the edge of the furrow. When the plants develop four or more true leaves, thin to one plant every 12-24 in. To get a head start on pepper production, many gardeners raise or buy transplants to set in the garden after danger of frost.
Provide peppers with an even moisture supply, but take care not to overwater. Chile wilt (phytophthora root rot) can be a major problem under wet conditions. On the other hand, insufficient water may lead to blossom-end rot.
Eggplant has growth characteristics similar to peppers. Lavender flowers are borne singly or in clusters like a tomato. Depending on the variety, fruit may vary in shape from oval to oblong with colors ranging from purplish-black to white. This plant is very sensitive to cold.
The Legumes
Legumes have the capacity to produce their own nitrogen from elemental nitrogen in the atmosphere. Thus, little if any additional nitrogen fertilizer is needed for the production of these crops. Rhizobium bacteria found in nodules on the roots "fix" atmospheric nitrogen into a form used by plants. Crops following legumes will also benefit from the nitrogen left in the soil by these plants. In soils where legumes have never been grown, the seed of the legume may have to be treated (inoculated) initially with the appropriate Rhizobium bacteria to begin the process. These bacteria are generally available through local nurseries or seed catalogs.
Green beans or snap beans are classified as either bush or pole types. Bush-type snap beans, as the name indicates, grow into small, compact plants. Pole beans have a climbing or twining characteristic, and require a trellis, fence, or other structure on which to climb. Pole beans are planted in the spring and will produce more beans over a longer time than bush beans. In warmer growing areas, however, bush beans can be planted in the spring for a summer crop or planted in the summer for a fall crop, thus making them an excellent crop for rotations with cool-season crops like radishes or leaf lettuce.
Bush beans are normally planted in rows, often on both sides of a raised vegetable bed. Pole beans can be planted in hills and allowed to grow up stakes formed in a tepee shape, or along a fence (4-8 in. apart).
Lima beans or butter beans are also available as either bush or pole types. Lima beans, however, require a longer time to mature. Varieties may vary from the large-seeded 'Fordhook' types to the smaller-seeded baby lima. Beans can be eaten in either the mature green stage or as dry beans. Dry Beans. Try your luck at raising beans for drying.
Dry beans are among the oldest of foods. Prehistoric people found that dry beans stored well and were easy to transport and prepare. Dry beans are popular because they are inexpensive and highly nutritious.
Pinto beans are a New Mexico favorite. Plant pinto beans in the spring, and plant again in mid-July for a second crop. Harvest pinto beans before the dry pods shatter. Pick individual pods or cut the entire plant just before the bottom pods shatter. Dry and thrash cut plants and store the beans for later use.
The Aztec bean has become popular in northern New Mexico home gardens. This large, white bean variety has been found in ancient Indian ruins. The Aztec bean is a vigorous climber and can easily climb 8-ft poles. Each plant can produce more than 1/2 lb of dry beans in ideal growing conditions. Soak the beans overnight before cooking; they will increase to four times their original size. Each cooked bean is bite-sized.
Other Beans. Consider other beans for the home garden. Mature, dry soybeans are excellent for winter use and for sprouting. Fava beans (horsebeans) are not true beans, but are related to vetch. Green fava beans are used as green shell beans, much like limas. Some people of Mediterranean descent have a genetic trait that causes a severe allergic reaction to fava beans. Fava beans prefer cool temperatures. Plant them at the same time as garden peas. Black-eyed peas are used in New Mexico as snap or dry peas. Although it has many names, this vegetable is neither a bean nor a pea, but a cowpea. Like beans, black-eyed peas require warm days and warm nights to develop properly.
Garden peas are cool-weather crops. In New Mexico, peas do not do well once warm weather arrives, so plant them in the spring as soon as the soil can be worked.
Garden peas are often classified into two types: the traditional English pea, which must be shelled, and edible-podded peas where both the peas and pods are eaten.
Pods of the English pea should be picked when plump, usually beginning on the bottom of the plant. Pick pods often so the plants will remain productive. Do not allow peas to become too mature or they will lose their sweetness. Harvest early in the morning when it's cool and use the peas as soon as possible to retain sweetness.
Edible-podded peas are often classified into two groups. "Stir-fry" types are often called sugar peas, snow peas, or China peas. Harvest when these pods are young before the peas begin to form in the pod (flat). Another group are called snap peas. Pods are allowed to become relatively thick and fleshy. Harvest before they lose their sweetness and become too fibrous. Snap peas can be eaten raw in salads, served raw with dips or relish trays, or cooked like green beans.
The Vining Crops or Cucurbits
Cucurbits are warm-season crops characterized by spreading vines and fleshy fruit with relatively hard rinds. Uses of these vine crops range from salads to desserts, cooked vegetables to snack foods.
Cucumbers are often planted on beds 36-72 in. apart to accommodate their spreading vines. Vines can also be trained up a fence or trellis for support. Fruit will be cleaner and have fewer rot problems if they are trellised. Some long, slender cucumbers tend to grow crooked, but cucumbers hanging from a support are usually straighter. When space is limited, home gardeners may want to try bush varieties, which are also good for pot culture and mini-gardens.
There are several types of cucumbers. Slicing cucumbers are usually used fresh, either alone or in salads. These long, cylindrical fruits are best when 6-8 in. long. If they are picked smaller than 6 in., slicing cucumbers can also be pickled. There are, however, some varieties specifically bred for pickling.
The lemon cucumber is popular in New Mexico gardens. This variety is the size and shape of a lemon and turns a lemon color when mature. This easy-to-grow, burpless cucumber has a flavor unlike most other cucumbers.
The Armenian cucumber has gained popularity in the past few years. The fruit grows 12-18 in. long and is about 2-3 in. wide. The skin is spineless with slight ridges and is greenish yellow in color. When allowed to grow too large before harvesting, Armenian cucumbers tend to be seedy. The Armenian cucumber has a mild flavor that many people enjoy.
Squash is a favorite in gardens. It is easy to grow, nutritious, and low in calories. Squash can be eaten raw, fried, boiled, steamed, baked, and even made into delicious pies.
Squash has been around for a long time. Archaeologists have discovered stems, seeds, and rinds in ancient cliff dwellings in the Southwest, indicating squash was grown some 1,500-2,000 years BC.
Squash fall into three main species of the genus Cucurbita: C. pepo, C. moschata, and C. maxima. Within these species are vegetables often commonly called pumpkins; therefore, the squash and pumpkin have no biological difference.
For the home gardener, however, squash are usually classified as summer or winter squash. Summer squash include varieties customarily eaten at an immature stage when the seeds are not fully developed and the rind is still tender. Types such as the zucchini, scalloped, and yellow crookneck or yellow straightneck are good summer squash.
Harvest winter squash when they are fully mature after the rind has hardened. Under proper conditions, these squash can be stored for several months for winter use. Pumpkins should be fully colored (orange).
The vegetable spaghetti squash is often listed in seed catalogues as a squash, although it is really a gourd. Its stringy, spaghetti-like strands can substitute for spaghetti, and it is an excellent addition to New Mexico gardens. Store spaghetti squash like winter squash.
It is important to provide squash with plenty of sunlight, space, rich soil, and moisture. Plant squash after danger of frost because the plants cannot tolerate freezing temperatures.
In areas where the frost-free period exceeds 150 days, gardeners can make two plantings of summer squash. Summer squash can produce edible fruits 7-8 weeks after seeding. Winter squash require more time, taking 80-120 days to mature.
In general, bush types of squash can be planted in hills 24-45 in. apart in rows 36-60 in. apart. Plant four to five seeds per hill. After seedlings appear, thin to the best two or three plants. Vining types of squash require more room to grow. Space hills 36-96 in. apart in rows 72-96 in. apart.
Irrigate squash deeply. Avoid sprinkler or overhead irrigation, which encourage foliar diseases such as powdery mildew. It is normal for squash leaves to droop slightly on hot, dry days, but they recover by morning. If not, water the plants.
Squash is a monoecious plant, that is, it bears unisexual flowers. Both sexes of flowers grow on the same plant. Male (staminate) flowers taper into the stem, while the female blossoms have a swollen ovary, or miniature squash at their base.
A common misconception is that because squash is a member of the same family as cucumbers, cantaloupes, and watermelon, these vegetables easily cross. This is not the case.
Winter squash should be well matured before storage. Cure winter squash by storing them at 80-85¡F for 10 days. This curing process hardens the rind and heals any cut surfaces. After curing, store squash in a dry location and lower temperatures to 55-60¡F.
Acorn squash is treated differently than other winter squash. Harvest when the bottoms of the fruit (where they touch soil) turn yellow to orange (green types). Do not cure acorn squash. Store them at 45-50¡F. High temperatures cause acorn squash to lose moisture and become stringy.
Melons
Cantaloupe and muskmelon are practically synonymous. Muskmelon is the term used in the Northeast, while cantaloupe is commonly used in other parts of the country. Cantaloupes grow best and develop the best flavor in hot, dry climates, making New Mexico an ideal place for them.
Cantaloupes perform best in moderately sandy soil. Plant by direct seeding after danger of frost. Sow 3-6 seeds in hills 4-6 ft apart. Thin to the best two to four seedlings. Seed can also be planted 1/2-3/4 in. deep, 12 in. apart in rows 60-84 in. wide.
When ripe, cantaloupes usually have a rough netting on the rind and an orange-colored flesh with a distinct aroma. As the melon matures, the color under the netting turns yellow and a crack develops around the stem where it is attached to the fruit. When mature the stem breaks away from the melon with little to slight pressure. This stage is called the "full-slip stage"-cantaloupes have their best flavor at this time.
Honeydew. The honeydew melon has a smooth, ivory rind and thick, light green flesh. Honeydew is sweet, but lacks the characteristic flavor of cantaloupe. Fruits can weigh 6 lb or more.
Casaba. The casaba is a melon with a truly distinct flavor. When mature, the outside rind turns bright golden yellow and wrinkled. Its flesh is thick and white, and the melon has a musk flavor. If stored in a cool, dry place, casaba keeps well for a month or more after harvest. It is a favorite of many native New Mexicans.
Crenshaw. The crenshaw melon usually has a salmon pink flesh. Melons are large and oval, pointed at the stem end. They can weigh up to 14 lb.
Watermelons. Watermelons are also members of the cucurbit family. Because they require a long growing season, choose an early-maturing variety in areas with shorter growing seasons. Watermelons require more room to spread than cantaloupes-at least 8-10 ft.
It is difficult to determine when a watermelon has reached maturity and is ready for harvest. Some gardeners look at the tendril closest to the melon. When the tendril turns brown and dries, it is an indication of maturity. This indication, however, is not always accurate because the tendril often dries up 7-10 days before the melon is fully mature, or the tendril may have had insect or mechanical damage that caused it to dry up.
Some gardeners use sound as a guide. When thumped, a green watermelon gives a ringing sound; when ripe, it gives a dull sound. This technique takes practice. Perhaps the surest sign of maturity is the appearance of the bottom surface where the melon has rested in the field. As the watermelon matures, the ground spot turns a rich banana yellow color.
Corn
Sweet corn is very popular among backyard gardeners because of the unbeatable fresh taste of homegrown corn. The roasting ear stage does not last long, so successive planting, or planting different varieties that mature at different times is recommended for continuous harvest.
Corn is wind pollinated. Pollen from the tassels of one plant fertilize the silk from another. To ensure good pollination, plant corn of the same variety in blocks of several short rows, rather than planting one or two long rows. Corn can also be planted in hills with three or four plants per hill to ensure good pollination.
Pollen from various types and varieties of corn can contaminate sweet corn, causing kernels to become starchy and lose their sweetness. This is especially true of some newer, extra-sweet varieties. Separate sweet corn varieties to ensure top quality and flavor.
Plant sweet corn in the garden after soil warms in the spring. Plant corn 1-2 in. deep, 3-4 in. apart. Thin plants to single stalks 8-12 in. apart. Extra-sweet or super-sweet varieties of sweet corn should be planted 1/2-1 in. deep and two weeks later than regular sweet corn for good germination.
Harvest sweet corn when kernels are in the milk dough stage. At this stage, silks are brown and dry. Kernels are fully expanded, but are tender and filled with an opaque, milky juice.
Regular sweet corn passes through its prime rapidly. If harvest is delayed, kernels become tough and starchy and lose their sweet flavor. Sweet corn also loses quality rapidly after it is picked. The sooner the corn is prepared after picking, the better the flavor. For improved sweetness, plant extra- or super-sweet varieties.
Popcorn is handled the same way as sweet corn. Many varieties do well in New Mexico. Some varieties have yellow kernels, while others have white kernels. Strawberry popcorn has small, mahogany red ears that resemble large strawberries. Choose a hull-less variety that produces more than one ear per stalk. Harvest popcorn ears when stalks and leaves are completely dry. After removing ears, cure them for about three weeks in a dry, well-ventilated area. Ears are ready to shell when kernels come off completely dry. Store shelled kernels in tightly sealed containers.
Okra
Okra is a tropical crop but can be grown successfully in most warm-season areas of the state where the average temperature is 65-95¡F. Varieties range from tall to dwarf, with smooth or ridged pods. Related to cotton, it is susceptible to most cotton diseases like verticillium and fusarium wilts. Only one flower per day will open on any given stem forming fruit that are green to creamy white in color. Harvest pods when they are relatively small (3-4 in. long) and tender.
SWEET POTATO CULTURE. The sweet potato (Ipomoea batatas) belongs
to the Convolvulaceae, or morning glory family. It is a native of tropical
America and is unrelated to the true yam, which is a climbing plant of the genus
Dioscorea and an Old World native. Several varieties of sweet
potatoes have been grown in Texas, including Puerto Rico, Goldrush, Redgold,
Allgold, Centennial, Jewel, and Red Velvet. By the 1950s the Puerto Rico was the
most prevalent variety in the state. Sweet potatoes grow best in light
sandy-loam soils with a clay subsoil. Before planting sweet potato fields should
be well drained and well worked to loosen the soil and promote the growth of
roots. Root sprouts and slips from vine cuttings are used in propagation and
planting. . The planting season starts in April or May and extends
through June; harvest takes place from August through October and sometimes into
November. Sweet potato production is often affected by severe cold or wet
weather conditions, insects such as the grasshopper, and diseases. Sweet
potatoes are subject to damage from relatively few insect pests, but a variety
of fungal and viral diseases attack both the growing plants and potatoes in
storage. The incidence of disease can be lessened by the use of disease-free
cuttings, treatment of the crops with fungicides, and careful harvest and curing
practices that minimize injuries and allow for healing of damaged skin.
It must be noted that all parts of the sweet potato plants are edible and that
growing them from slips or cuttings is a common practice. Tubers used for making
cuttings should not have been treated with any substance that prevents the eyes
from developing into shoots. I have used both my own tubers or store bought
tubers for growing the shoots for rooting and plant into the garden when the
weather is reliably worm. Cuttings taken from the new shoots of a sweet potato
can easily be rooted by placing them in a jar of water on the window sill. When
the roots have developed to one to 4 inches in length they can then be potted up
or planted in the garden if the weather is adequately warm. (no frost) I
additional slips are needed cuttings can be taken from the longer cuttings
rooted and then planted out. If desired, before the first frost cuttings can be
taken from the existing healthy plants, rooted in water and carried over to the
next spring in a bright window or greenhouse. One such cutting will be adequate
to supply you with enough additional cutting for the next season as the sweet
potato is a perennial in warm climates.