Growing in the Home Garden

The home gardener needs to follow the following 6 procedures in order to produce a continuous yield of high quality tomato fruit over the entire growing season.

Home Tomato Garden Site Selection

The ideal site is one that is in full sun in the morning hours and partial shade in the afternoon hours.  In areas of frequent cloud cover where sun light intensity and duration are limited, full sun all day would be desirable.  High light intensity exposure in the afternoon can reduce fruit set and result in poor fruit quality.  Avoid small depressions and the top of knolls where air temperature extremes can commonly occur, and/or where air movement is restricted.  Avoid sites that are downwind of power or industrial plants, or fields devoted to row crop production or fruit orchards where agricultural chemicals are frequently used for weed, disease and insect control as the tomato plant is sensitive to emission gases and pest chemicals.  The site should be such that there is light air movement, but not where strong winds are frequent. It is not recommended to plant tomatoes when the previous crop was tomato. The use a winter (between seasons) cover crop, however, can serve as a means of crop rotation, allowing repeated tomato plantings unless there occurs seedling loss due to soil organisms that become pathogenic, therefore, requiring selection of another planting site.

Home Tomato Garden Soil Requirements

The “ideal” soil texture is either a loam, sandy clay loam or silt loam with a top soil depth of at least 6 inches.  Sandy, clay and organic soils as well as shallow soils are the least desirable, although successful plant production and good fruit yields can be obtained with properly applied management procedures. The soil should easily drain after a rainfall event or applied irrigation water.  The soil water pH should range between 5.8 to 6.5 and the essential plant nutrient element contents be within the “sufficiency” range based on a soil test determination.  Based on a soil test recommendation when either lime and/or fertilizer treatments are required, in the fall evenly broadcast limestone (dolomitic) and mix into the soil by spading to the soil surface depth.  In the spring, evenly broadcast the recommended fertilizer and mix into the soil by spading to the surface soil depth. In order to maintain soil structure, do not roto till the soil, or cultivate the soil when wet.  A winter cover crop can be beneficial as a means of increasing the organic matter content of the soil and improving soil tilth.  Either a grass or legume cover crop is appropriate.  Be sure to fall plant in sufficient time to ensure good plant growth before cold weather sets in.  Adding a nitrogen (N) plus potassium (K) containing general purpose fertilizer maybe needed to enhance good plant growth. Turn the cover crop over by spading the soil to the surface soil depth at least 4 weeks prior to setting tomato transplants. A cover crop can also be a means of controlling the potential for pathogens accumulating in the soil with repeated planting of tomato.

Home Garden Tomato Variety Selection

There are 3 major factors to be considered when selecting a variety, whether determinate or indeterminate, and then maturity class (early, mid-season, late), and resistance to diseases and insects.  Other factors are fruit characteristics, such as size and color. Fruit flavor is somewhat related to variety, although growing conditions is equally a factor as well as the length of time on the plant before harvest, longer on the plant, the more likely the higher will be the fruit flavor. A wide range of Heirloom varieties are readily available, offering the grower a range of fruiting characteristics including fruit color and size. However, some of these varieties may be sensitive to particular environmental conditions, such as moisture, light intensity and temperature stress as well as lacking resistance to commonly occurring diseases and insects.  Variety selection should be made based on expected use and for meeting the needs for daily consumption and other uses, such as the making of sauces and for canning.

Home Garden Tomato Plant Fertilization

The tomato plant is considered a “moderate to heavy” feeder, therefore, plant growth as well as fruit yield and quality will be significantly affected by the availability of the essential major nutrient elements, particularly nitrogen (N) and potassium (K) as well as the micronutrients boron (B) and zinc (Zn).  Over fertilization is as detrimental to plant growth and fruit yield as deficiencies of the major nutrient elements, with the major nutrient element frequently over applied being phosphorus (P).  In addition, high nitrogen (N) will reduce flowering and fruit set.  Sufficient potassium (K) is needed to ensure good fruit quality.  The lack of sufficient calcium (Ca) as well as magnesium (Mg) can result in the occurrence of blossom-end rot in developing fruit.  If the soil water pH is maintained within the desired range, 5.8 to 6.5, by liming using dolomitic limestone, the rate determined based on a soil test recommendation, the deficiency of either of these elements is not likely to occur.  The use of a general purpose fertilizer, or an organic source, such as composted animal manure, is not recommended and can lead to nutrient element insufficiencies that can be difficult to correct.  Have the soil tested and follow the soil test recommendation using fertilizer materials of known elemental content. Be equally aware of excesses as well as deficiencies. A good indicator of over fertilization is vigorous vegetative plant growth, the rapid development of suckers coupled with low fruit set and yield. If the soil fertility level is within the desired range and a soil test-based lime and fertilizer program followed, supplemental fertilization will not be required during the growing season. Nutrient element insufficiencies occurring during the growing season are difficult to correct as supplemental treatments are usually ineffective.

Home Garden Tomato Plant Cultural Practices

Depending on what tomato variety is selected, either determinate or indeterminate, plant spacing and control of the growth habit is essential for high fruit yields and good fruit quality.  Close plant spacing (less than 18 inches in the row and 36 inches between rows) can reduce fruit yield and quality. For the indeterminate varieties, the plant will require support to hold the plant upright, either tied to a stake or fence, or maintained within an upright cage.  The major cultural requirement is to remove both axial and fruit stem suckers as they appear. Axial suckers not removed will develop into fruiting stems, while fruit cluster vegetative stems will draw carbohydrates from the developing fruit, resulting in reduced fruit size.   In some instances, the removing of fruit (known as fruit pruning) may be required to control the number of fruit on each cluster, ensuring uniform fruit size as well as a means of sustaining further fruit set and development.  Removing slow developing fruit, and the maintaining of a consistent number of fruit per cluster will increase fruit quality.  A tomato plant tends to maintain a constant weight of fruit on the plant during its fruiting period, therefore, fruit number and size will counter each other, large fruit, fewer number; small fruit, larger number.  Fruit disorders (blossom-end rot, cracking, catfacing, etc.) may not appear until 10 to 14 days after a stressful environmental event, such as cool or hot weather, cloudy or high light intensity conditions, excessive rainfall or a period of drought.  As the plant matures, remove and discard senescing leaves and those that have been damaged mechanically or by insects. Do not leave removed foliage in the garden site. Toward the end of the fruiting period, topping the plant (removing the growing terminal) will result in more rapid fruit development and an increase in fruit size for those fruit existing on the plant.

Home Garden Tomato Plant Moisture Requirements

A mature tomato plant will transpire up to a quart of water per day depending on weather conditions, stage of plant growth and fruit load.  Consistency of water availability is essential to maintain vigorous plant growth, uniform fruit set, and steady fruit development.  Lack of fruit set is frequently related to moisture stress correlated with hot dry environmental conditions, or low air temperatures and reduced light intensity.  One of the major factors associated with the occurrence of the fruit disorder, blossom-end rot, is moisture stress.  If natural rainfall is insufficient to keep the soil moist (not wet), in the early evening, apply water to the soil around the plant out to 12 inches. The application of mulch around the base of the tomato plant may be helpful in reducing moisture loss from the soil by evaporation; however, mulch will tend to keep the soil cool and moist that may, in turn, reduce plant growth and fruit yield.  Applying mulch between the plants and the rows can help to keep the surrounding soil moist while providing a foot path between the plant rows.

Home Garden Tomato Plant Insect and Disease Control

Selecting only those varieties that have genetic resistance to diseases and insects is desired. The occurrence of disease and insect pests can be related to cultural practices, such a moisture control, plant nutritional status, air movement around the plant and weather conditions. The grower should be prepared to deal with infestations when they occur using only those control chemicals label-approved for the tomato plant and the pest to be controlled.

Monitoring the plant on a daily basis is essential to quickly discover a potential infestation. Early identification of a pest infestation is essential in terms of effective control as after the fact, control may be difficult or impossible. Proper identification of the pest affecting the plant is essential before applying any control measures. The grower should be aware of those pests in the region that commonly affect tomato plants as well as the sensitivity of the chosen variety to a particular pest so that proper control measures can be applied, if and when an infestation occurs.  Foliage that has been affected by the presence of disease organisms and insects should be quickly removed from the plant and from the garden site.