Growing a Great Tomato
By John Porter, WVU Extension Service Kanawha County agriculture agent
First-time vegetable gardeners often begin their gardening passion with one specific plant – the tomato. Even people who have little interest in growing a full-scale vegetable garden often have a tomato plant or two in an ornamental bed or in a container on a patio.
This interest in homegrown tomatoes lies both in nostalgia for the fresh-off-the-vine and still-warm-from-the-sun taste of a tomato grown by long-gone relative and in a desire for the good taste and fresh juiciness that can’t be found even in in-season tomatoes at the grocery store. Whatever the reason, tomatoes find their way in to the hearts and gardens of many new gardeners. With a little skill, a little patience, and maybe even a little luck, you can grow your own great homegrown tomato.
Selecting Tomato Varieties
Cultivar considerations will affect the type of tomato that you grow, the flavor profile of the fruit, the disease resistance of the plant, and even the overall shape and productivity of the plant itself. The first step in growing the “perfect” tomato is to select the appropriate cultivar for the desired characteristics of a tomato that has some degree of disease resistance.
There are several different tomato fruit types, and each type has characteristics that lend themselves to different uses. Slicing tomatoes are often medium- to large-size fruits that are used for such things as slicing onto sandwiches and eating fresh. They also can be used for creating tomato sauces. Cherry tomatoes are marble-size fruits commonly used for fresh eating in salads and also for raisin-size dried tomatoes. Paste or canning tomatoes are often oblong-shaped tomatoes that have a thicker, less-watery flesh good for canning salsas and sauces and for drying. Salad or pear tomatoes are small, pear-shaped fruits that are good in salads; they can also be dried.
Determinate vs. Indeterminate
Tomato plants can have one of two major growth habits – determinate or indeterminate.
Determinate tomatoes are often referred to as “bush” tomatoes since their growth is shorter and bushier than that of indeterminate plants. These plants are often easier to stake because they have a determined height. They do have a limited harvest period and once all of the fruits are harvested, the plant is barren for the remainder of the season.
Indeterminate tomatoes are often referred to as “vining” tomatoes since they grow continuously throughout the season. The plant will continue growing taller as long as water, nutrients, and proper weather conditions are present. As a result, they produce fruit throughout the season, often until killed by frost.
Several common diseases and pests affect tomato growth and health. Selecting cultivars that are resistant to these diseases can reduce the likelihood that a plant will become infected, improving both the yield and the quality of fruit. Many newer cultivars of tomato often have resistance to one or more of these common diseases. Many heirloom varieties, on the other hand, lack these resistances and may require more maintenance or treatment to deter infection. Plant tags or descriptions in catalogs often list these resistances in the form of a letter code system, and each catalog should have a table or list of what each letter represents.
Table 1 Common tomato diseases for which resistance is available.
Selecting and Preparing the Right Site
Tomato success also depends a great deal on the site where they are planted. Whether they are grown in the garden or in a container, some basic requirements must be considered when selecting and preparing the site where tomatoes are to be grown.
- Light is an important factor in the growth of tomatoes. Plants should receive between six and eight hours of sunlight per day. Lack of light can result in poor plant vigor and delayed fruit development and ripening. It can even affect the sweetness of the ripened fruit.
- Soil is also important for healthy, vigorous plants. The soil should be rich in organic material, which helps retain moisture and nutrients in the soil. If the soil is heavy clay or sandy, it should be amended with 2 to 3 inches of compost or other organic manure, which should be cultivated into the top 6 to 8 inches of the garden bed. For containers, a well-blended potting soil should be sufficient for one season’s growth.
- Fertility is important since it ensures that tomatoes receive the proper nutrients for growth. It is important to test soil using the free testing service offered through the WVU Soil Testing Lab and amend the soil with lime and fertilizer according to the lab’s recommendations. If a soil test has not been performed, apply 40 pounds of a general fertilizer such as 5-10-10 per 1000 square feet. Lime is important to maintain nutrient balances and avoid blossom end rot of the fruit, which results from a calcium deficiency.
After the plants have flowered, an application of about 1 tablespoon of sodium nitrate will boost growth and vigor. This side-dressing should be applied about 3 inches away from the plant stem and can be left on the soil surface until rain washes it into the soil.
Planting and Maintaining Tomato Plants
After the site is prepared, the next step is to plant the tomato. Tomatoes are unusual in that you can bury them much deeper than other plants. Tomato transplants can be buried 1 to 2 inches deeper than they grew in the pot or plant bed. This allows roots to grow along the buried area of stem and establish a much healthier plant. Tomato plants should be spaced 18 to 24 inches apart in rows 3 feet apart or within raised beds. Indeterminate tomatoes that are staked can be planted at 18 inches, whereas determinate tomatoes need the wider 24-inch spacing.
After they are planted, the transplants should be watered in. At this point, a transplant or starter fertilizer can be applied. This fertilizer is usually higher in phosphorous and potassium to encourage root growth. Commercial preparations are available and recommended, but a homemade solution can be made by dissolving 1 cup of 5-10-10 fertilizer in 4 gallons of water.
Many tomato varieties benefit from staking. This practice keeps the plants off of the ground, resulting in cleaner produce and fewer diseases. Many determinate, or bush-type, plants do not require staking unless fruit set is heavy. Indeterminate, or vine-type, generally do require staking. Tomatoes should be staked on a 6-foot stake driven about 1foot into the ground about 3 to 5 inches away from the plant. These stakes can be wooden, metal, fiberglass, or even bamboo. The plants should be tied loosely to the stake with a soft material, such as a strip of cloth, nylon stocking, or twine. Other support systems, such as cages, can also be used successfully.
Watering is a major key in the good health of any garden plant. Plants should receive the equivalent of 1 inch of rainfall per week. If rainfall is insufficient, watering will need to be done regularly. A weekly watering requires that the soil is moistened to a depth of 6 to 8 inches. The leaves, stems, and fruits of tomatoes should not be splashed with water, especially in the evening because moisture can lead to disease issues. Irregular watering, such as too little or too much moisture, can contribute to the blossom end rot disorder by limiting calcium uptake of the plant.
Mulching can serve three major purposes for tomatoes.
- Weed control will increase the vigor of tomatoes and eliminate a potential source of insects and diseases.
- Retention of moisture will reduce the potential for blossom end rot and encourage even and healthy plant growth.
- Reduction in disease spreading – Several plant diseases, including late blight, are spread by water splashing from the soil onto stems and leaves. If a mulch is provided, splashing is limited and diseases can be suppressed.
For large plantings, the use of black plastic mulch may be advisable. Many home gardeners, however, find benefit in using straw or newspaper as a mulch. Straw should be applied about 6 inches deep after the plants have grown for a few weeks. Several thicknesses of newspaper can be laid at the base of the plant, or newspaper can be shredded and applied in a manner similar to straw.
Dealing with Problems: Pests, Diseases and Disorders
Pests and Diseases
In addition to the diseases discussed above, several insect pests can also affect tomatoes. For best results, contact your county WVU Extension agent for assistance in diagnosing and controlling each problem. Finding problems early and diagnosing each problem are key in dealing with issues safely and effectively.
Several common tomato issues are related to stress and physical issues rather than pests or diseases. One example is blossom end rot, which has been discussed previously. Several other issues that affect tomato quality can be controlled by the plant environment.
Hard white stripes in tomatoes are often a result of excessive temperatures during ripening. Some control may be available by proving shade to the plants with shade cloth or other material during ripening. The effect may also be lessened by maintaining proper potassium levels in the soil.
Catfacing is the presence of large indentions in tomatoes. Studies indicate that this may be a result of cool temperatures during flowering, most likely caused by incomplete pollination.
Cracking occurs when internal growth occurs faster than external growth. This is most likely in times of high moisture. Some varieties are more susceptible to cracking, but maintaining even soil moisture is key in controlling this disorder.
Blossom end rot is the result of a lack of calcium in the fruit. Calcium is a major component in the pectins that provide structure in fruit, and when it is unavailable the bottom of the fruits decay. There are two major causes of calcium deficiency in tomatoes – its absence in the soil and uneven watering. A soil test will determine the amount of calcium in the soil, and amendment can be made with agricultural lime to ensure that it is present in the soil. The most common cause of blossom end rot, though, is extremes in soil moisture. Too little moisture means that roots cannot uptake minerals, since they are dissolved in water. Too much water kills the tiny root hairs on the roots and inhibits water uptake. To ensure proper soil moisture, provide irrigation during summer dry spells and make sure that soil drains well. To encourage drainage in soil, amend heavy soils such as clay soils with organic matter like compost or composted manure.