GROWING TOMATOES CAGED OR TRELLISED
Roland E. Roberts
Extension Horticulturist
The tomato, Lycopersicon lycopersicum is a sub-tropical plant. In spite of this tomatoes can grow very productively for Northwest Texas gardeners who use cage culture or trellis culture. We are blessed with naturally fertile, well drained loamy sands, sandy loams and clay loam soils in this region. Cage culture or trellis culture — with cage-wraps or floating row covers of spun-bonded polypropylene or perforated polyethylene – moderates extremes of temperature and wind, protects plants from virus-bearing insects and supports stems and fruit above the soil surface. Tomato gardening with cages produces abundant high quality tomatoes, and gardeners have lots of fun seeing how well the plants grow.
Soil Preparation
All tomato garden soils can be enhanced by receiving additional organic matter. Compost and composted cow manure can be applied safely at a rate of no more than 50 pounds per 100 square feet of garden area. Chemical makeup of composts varies widely. Too much highly fertile compost can hurt tomato roots because it raises soluble salt concentration of the soil to a toxic level. Sphagnum peat is a wonderful source of organic matter which adds little or no available fertility but acts as a storehouse for plant-available essential elements from fertilizer applied before planting and during the growing season. Limit peat application rates to 50 to 60 pounds per 100 square feet to make its use economical.
Several weeks before planting, take a soil sample and have it tested by the Extension Service or a reliable private laboratory. Some homes are built on former shores of playa lakes where highly alkaline materials in the lake floor have been mixed with surrounding soil by developers. Urban garden soils near new homes often have been mixed with construction “leftovers” during smoothing of surface soil and grading around new homes. These leftovers include cement, brick mortar and caliche (calcium sulfate) from digging foundation footings. Soil test results will tell you how to treat you soil before planting tomatoes.
Spade fork or till soil to a depth of 12 inches or more. Break clods to provide a granular structure. Spade in or till in 5 pounds of agricultural sulfur per 100 square feet if only if your soil test report says to. If your soil is a tight, compacted sandy loam or clay-loam with high pH (above 7.8) and/or you irrigate with water f rom Lake Meredith, it may help to till in 5 to 6 lb gypsum per 100 square feet to help lower the sodium salt concentration. In late fall or early spring, mix organic materials thoroughly into your soil to a depth of 6 to 12 inches. Till soil when it is moist enough to break apart easily but not so wet that it sticks to garden tools.
Fertilizing
Please take a soil sample and have it tested! Knowledge about the fertility of your soil is important to your being a successful tomato gardener. Soil sampling kits with instructions are available from your county Extension agent. If a specific fertilizer recommendation (soil test) has not been made, apply one pound of 16-20-0 per 100 square feet and spade fork or till it at least 6 inches deep into the soil before planting. Plan to fertilize at least 25 square feet of garden area per plant for individual tomato plants. Forms, instructions, and sample bags for soil sampling are available at our county Extension Service office. Water newly set transplants with solution of one level tablespoon of Miracid (30-10-10 plus trace elements) per gallon of water, pouring at least one quart at the base of each plant.
Starting when tiny fruit are first noticed, side-dress tomato plants with nitrogen. Apply one level tablespoon of urea (45-0-0) per plant by sprinkling it uniformly over a six-foot diameter, circular pattern on the soil or over the mulch around each plant. Immediately irrigate with one inch of water. One inch of water over 28 square feet (a circle with radius of 3 feet) is 16 gallons. One inch of water over 50 square feet (a circle with radius of 4 feet) is 31 gallons.
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Sunlight
Tomatoes grow best in full sunlight. They require at least 6 hours of full sunlight per day such as they might get on the east side of a north/south-running fence. If light is inadequate, tomatoes will survive but yield poorly.
Space
Space required for tomato plants will vary with the variety and growing method. Trellised plants should be about 24 inches apart in the row, with 4 to 6 feet between rows. Caged plants should be spaced at least 6 feet apart each way. See Figure 1. You can space dwarf varieties 12-18 inches apart. Roots of a healthy tomato plant radiate at least 3 feet out from the stem base.
Build and Use Perforated Plastic or Grow-Web Wrapped Cages
Tomatoes are tender subtropical plants which benefit from protection against low temperature, wind, hail, insects and diseases. Grow-Web gives this protection. Tomatoes inside wrapped cages are happier. Use concrete reinforcing wire to form a cage that is 18 to 24 inches in diameter and 5 feet in height. Wrap cage with perforated plastic (Vispore) or spun-bonded polypropylene (Grow-Web) and clamp the material to the wire with clothes pins to keep it in place. The wrapped cage will slow wind, keep air and soil warmer around plant, prevent entry into cage by virus-carrying insects, and let in plenty of light. When leaves touch the wrap,
unwrap the cage and drape the wrap over and around the cage to continue repelling insects while liberating the plant to grow and set fruit.
Erect or Grow Windbreaks
Tomato plants are not wind tolerant. To reach its potential for yield and quality, the tomato plant must be protected from stresses imposed by our normally wonderful West Texas climate. Windbreaks can be grown or constructed. Elbon rye, triticale, and tall-growing wheat started the previous September or October work well. Tall-growing sorghum and sunflowers make good windbreaks and offer some hail protection. Newly transplanted tomatoes can be protected form wind with shingles, shakes, boards, or fencing. Windbreaks are valuable protection for cages to prevent them from being blown over. For every foot taller windbreak plants are than crop plants there will be some protection to crop plants outward at least 10 feet from the windbreak row.
Planting
Plant tomatoes on raised beds in clay-loam soil to simplify watering and improve soil aeration. In sandy-loam soils where drip or sprinkler irrigation will be used, plants can be planted flat with a circular berm of 18 to 24 Inches diameter. The berm or dam is formed to prevent irrigation water from flowing away from the plant. Set tomato plants in the spring as soon as danger of frost is past or earlier if wrapped cages are used. Plant potted tomato plants one to two inches deeper than the surface in the pot. Covering stem up to just above the point of attachment of the two cotyledon leaves (seed leaves) is a good guide. For a fall tomato crop, transplant about 120 days before the usual first frost. Select plants that are dark green, medium-height, heavy-stemmed, and without flowers or fruit. To grow plants at home, plant seed 5 weeks before the anticipated transplanting date. Set the plants slightly deeper in the garden than the original soil level. (See Figure 2.) Plant in late afternoon or early evening to reduce drying and wind damage. Erect windbreaks and apply a starter solution after each plant is set into the soil. Water in each plant immediately after planting. After a few days, move the windbreak far enough from the plants so that it does not cast a shadow on the plants.
Apply and Manitain Deep Layer of Mulch
Mulch conserves soil moisture, maintains optimum soil temperature, encourages an extensive root system, and prevents weed growth. The optimum root zone temperature for tomato is 75 degrees F. Apply and maintain four to six inches depth of clean wheat straw, or grass clippings, starting as soon as the soil temperature has reached 70 degrees F. Mulch outward at least four to six feet from stem (center) of plant. Under mulch, roots grow in soil right to the surface. Plants mulched in this manner will be much more productive than un-mulched plants. Most fruit which touch dry mulch will not rot as they do when resting on moist soil.
Caging or Trellising
You will lose tomato fruits from soil rot if you let them touch the ground. A mulch offers some protection, but caging or trellising tomato plants is more helpful, and well worth the effort. Wire cages made of reinforcing wire provide excellent support for tomato plants. (See Figure 3.) These cages can be made in various heights, but should be 18 inches in diameter. Cages of 24″ diameter are too wide to allow easy access to early set fruit unless you have very long arms. Place cages over tomato plants early in their growth. Each cage can support one tomato plant. Anchor cages firmly to the ground with wooden stakes to prevent them from toppling over as the plants grow. Suckering or pruning the plants is not necessary when you use cages. Don’t keep foliage in cage. Encourage branches to grow out the sides starting at the second rung. Plant branches will grow out the top eventually.
Do not prune plants of determinate hybrids if you plan to trellis and support them with twine woven around wooden stakes.
Irrigation
The tomato plant is a water spender. It can not be conditioned to thrive on limited soil moisture. Consequences of soil moisture deficit are aborted blossoms, blossom end rot, radial fruit cracking, small fruit and lower yield. Also, drought stress restricts leaf growth which results in sunburn of fruit directly exposed to strong sunlight.
Keep Soil Moisture Near Optimum
Tomato roots will not grow in dry soil to find moist soil. Maintain optimum soil moisture from the center of the plant outward at least three to four feet to encourage maximum root development. This fosters optimum plant health and highest possible fruit quality and yield.
How Much Water
I observed that roots of a healthy tomato plant with full fruit load will have grown outward three to four feet from the base of the stem in all directions. This is an area around the plant of over 28 square feet for a 3-foot radius circle and over 50 square feet for a circle with a 4-foot radius. One inch of water over 28 square feet (a circle with radius of 3 feet) is about 16 gallons. One inch of water over 50 square feet (a circle with radius of 4 feet) is about 31 gallons. A half inch diameter hose delivers about 3 gallons/minute at 50 to 60 psi. Know the delivery rate of your irrigation system, and run your system long enough to provide desired number of gallons.
How Frequently to Water
The soil area inhabited by tomato roots requires irrigation every 3 to 5 days depending on the temperature, sunlight and wind. Required volume of water will increase as the plant grows larger. I have found that by early to midsummer I irrigated every other day to every 3 days to maintain soil moisture near optimum. Continuous deep mulch over soil surface out at least 4 feet from stem will greatly increase water use efficiency.
Care During the Season: Inspect Plants for Insects and Diseases
Inspect Lower Leaf Underside for Mites. Mites seem to get started each spring on the lower surface of oldest tomato leaves nearest the ground. You may need a magnifying glass to see the two-spotted spider mites.
Inspect Growing Tips and Upper Leaves for Aphids. Aphids go for young succulent growth in emerging young leaves in growing tips at top of plant. When aphids are confined to growing tips, one can often dislodge them with a fine, strong stream of water or insecticide aimed right at the little cluster of aphids.
Inspect Lower Leaves and Fruit Calyx for Pinworm. Pinworm adults (tiny nocturnal moths) love to lay eggs on lower surface of bottom leaves near center of plant. From there they spread upward on the plant acting much like leaf miners and rolling the leaf around them as they build their little cocoon in which to pupate. Pheromone traps combined with timely use of Bacillus thuringiensis will control pinworm in most gardens.
Insect Control
More than a dozen insects attack tomatoes. Some attack only the fruit, some only the foliage. Others feed on both fruit and leaves. Failure to control insects may result in complete defoliation of plants or total loss of the crop.
Cutworms, attack seedlings or small transplants by cutting off plants at or slightly below the soil surface. These pests stay in the soil and feed at night. A few cutworms can destroy a complete stand of plants. Paper or metal collars placed around plants offer some protection from cutworms. For best results, apply recommended insecticides to the soil before planting.
Aphids, often called plant lice, are small, soft-bodied insects. They attack tomatoes at any stage of development by sucking juices from plants, and can transmit some diseases to tomatoes. Aphids build up large populations rapidly and should be treated when colonies first appear on the plant.
Leaf miners are the immature stages of small flies. The fly lays eggs between the upper and lower surfaces of leaves. When the eggs hatch, the small larvae tunnel through the leaf, destroying the tissue. Leaf miners attack tomatoes in all stages of growth; however, they do more damage to young plants. Apply insecticides as soon as you see mines in the leaves. Two or three applications at weekly intervals may be needed to control this pest.
Spider mites are one of the most serious tomato pests. They are greenish or reddish and very small. Spider mites suck juices from the leaves. Heavy infestations cause the leaves to turn yellow and drop off. Apply insecticide when mites or damaged areas are first seen on plants. Control is often difficult, and 2-4 applications at 5-day intervals may be necessary.
Leafhoppers are small, wedge-shaped insects which suck plant juices. They cause discoloration, curling and stunting of leaves. They also transmit certain plant diseases. Treat leafhoppers when they are seen on plants.
Flea beetles range from 1/16-1/4 inch long. They are usually black or brown, but some are metallic blue or green, or striped. Flea beetles eat tiny holes in foliage, and heavy populations can defoliate entire plants. Begin treatment for flea beetles when both damage and beetles are observed on plants.
Whiteflies are very small, white, aphid-like insects that suck juices from the undersides of the leaves. Immature stages are scale-like and are attached to the bottom of leaves. Heavy populations can cause small fruit and blooms to drop off and can defoliate the lant. Treat before populations build up and become established.
Stinkbugs suck juices from leaves, stems and fruit. Heavy infestations can cause blooms to shed. Punctured fruit show hard, light colored spots beneath the peel. Treat for stinkbugs when you see them on foliage or fruit.
Tomato fruitworms feed on the tomato fruit. One larva may damage several small fruit. Damaged fruit may fall off or ripen prematurely. For best control, treat when larvae are small.
Tomato hornworms are about 3 inches long when fully grown. They are green with slanted bars on the sides and a horn-like projection on the posterior end. They feed on foliage and fruit. One larva may damage several fruit. Tomato hornworms can defoliate a tomato plant almost overnight. Hand picking is an effective control measure in small plantings. Apply chemical treatment as soon as you notice larvae and damage.
Tomato pinworms are small, dark, banded larvae. They are about 1/4 inch long when fully grown. The young larvae are leaf miners. Larger larvae tie leaves together, feed on leaves and bore into fruit. Begin treatment as soon as larvae are detected. Several treatments at weekly intervals may be necessary for control.
Thrips are small, slender, agile bugs 1/16 go 1/8 ” long, with 4 feather-like, hair-fringed wings. They live in flowers and vegetative tips where they can hurt new growth of young plants.
Keys to Good Insect Control |
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| 1. | Identify the insect pest. |
| 2. | Choose the proper insecticide for the specific pest |
| 3. | Use the recommended concentration and amount of insecticide |
| 4. | Cover the plant thoroughly with insecticide |
| Before using any insecticide, READ THE LABEL and follow all directions and restrictions. For up-to date chemical controls for insects and diseases, please consult control guides available from your county Extension agent. | |
Diseases
Diseases can be a serious problem in tomato production. Damping-off often causes serious losses if preventive measures ;are not taken. Plant tomatoes on a raised bed so the soil around the plants does not become “waterlogged”. Young plants in a saturated soil are more subject to damping-off. Use soil applications of an approved fungicide if damping-off occurs.
Tomato foliage is most prone to disease attack during fruit set and later stages of plant development. Early blight, gray leafspot and leaf mold are three of the most common leaf spots.
Early blight appears as large, dark, circular spots with concentric markings on the lower foliage. It is found first on the lower foliage and spreads rapidly up the plant. Gray leafspot causes small, grayish-brown, shiny spots on the lower foliage. Leaves turn yellow and drop off as the disease develops. Leaf mold is marked by yellowish-green blotches on the upper side of the leaf and olive-colored lesions on the lower side. To effectively control these diseases, apply a foliar fungicide every 7-10 days once the disease is detected. Repeat applications as long as the foliage is wet daily by dew, fog or intermittent rain, and the daytime temperature remains under 95 degrees F.
Late blight may attack foliage, but it is primarily a problem on tomato fruit in Texas. Fruit near the ground decays rapidly during periods of high rainfall, and is marked by a firm, greenish-brown decay which does not rupture the skin.
Soil rot may occur when the fruit touches or grows near the soil. Damaged fruit decays rapidly, and affected areas are cracked and watery. To avoid soil rot, make sure that the fruit does not touch the soil by mulching, supporting the plant or using fungicides.
Fusarium wilt is a soil-borne fungus which causes rapid wilting of plants. Close examination of the stems reveals a brown discoloration. To control this disease, use only resistant varieties. Most varieties currently available are resistant to fusarium wilt. Chemical control is not effective.
Root knot is caused by nematodes present in many soils. Affected plants are stunted, yellow and appear to be low in fertility. Infected roots have galls which prevent normal uptake of nutrients. Prevent nematode buildup by maintaining high organic matter in soil. Control nematodes by using nematicides, and use resistant varieties when you suspect a nematode population.
Tobacco mosaic, curly top and cucumber mosaic are three of the most common viruses which attack tomatoes. To control viruses, buy only healthy plants, avoid excessive handling of plants, follow a good insect control program, and remove all virus-affected plants as soon as possible.
Curlytop and Tomato Spotted Wilt viruses can be prevented by wrapping cages in spun-bonded polypropylene or perforated polyethylene.
Read instructions thoroughly before using a fungicide. When spraying tomatoes, cover all foliage with fungicide for adequate disease control.
Harvesting
Tomato fruit do not ripen on the plant any better than off the plant if picked when pink color is visible on the blossom end (side facing the ground) and held at room temperature in light or dark. This is a truth and reality that is hard for many people to believe. Harvesting fruit when fruit are just beginning to turn pink at the blossom end will maximize both quality and yield by getting them out of harm’s way. After picking remove the caylx (stem) to prevent puncture. Wise tomato growers continue to harvest from the same plants all summer into fall and right up to first frost.
Pick tomatoes at full color for best quality. When temperatures exceed 85 degrees F., fruits allowed to ripen on the vine may become yellowish-orange rather than red. At this time, it is best to pick the tomatoes at the pink stage and allow them to ripen indoors at temperatures between 70 to 55 degress Farenheit for best color development. Exposure of immature fruit to temperatures below 55 degrees F. prevents quality ripening. Tomato fruit suffer chilling injury when stored in refrigerators.
Maintain Plant Health
By mid-season, older leaves at base of caged plants become infected with Early Blight or infested with pinworm. These leaves are shaded by those above and no longer benefit fruit growth. All nonproductive plant tissue (fruiting trusses, old yellowing or diseased leaves, spindly non-fruiting stems) can be removed from the older (lower) regions of the plant to let in more sunlight.
Long rotation (4 years) will prevent soil borne diseases and nematodes from becoming a problem. Do not plant an area to tomato or any other member of the nightshade family (includes potato, pepper, eggplant, tomato) or okra any more often than once every 4 years.
Keep Area Around Plants Mulched
Mulch, mulch, mulch — mulching can not be overemphasized for West Texas tomato health, both in commercial fresh market and home garden plantings. Mulching has been strongly emphasized in horticulture education for generations as an important technique for promoting plant health. Good sources of mulch include clean, dry wheat straw, rye straw, alfalfa, vetch, crimson clover, sorghum, haygrazer, also lawn clippings which have been allowed to heat to over 140 degrees F. for 24 to 48 hours in plastic bags to kill seeds and rhizomes.
The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended, and no endorsement by the Cooperative Extension Service is implied. Educational programs conducted by the Texas Agricultural Extension Service serve people of all ages, regardless of socioeconomic level, race, color, sex, religion, disability or national origin.
The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts Cooperating.
