Tomato Information

UF/IFAS “Tomato in the Florida Garden” Publication

Choosing the Right Variety

Selecting the right tomato variety is one of your most important decisions. Failure to select the most suitable variety may lead to a disappointing crop.

When choosing your tomato plants consider the following characteristics:

Disease Resistance: Varieties selected for Florida must have resistance to several diseases. “Letters” on the plant label indicate resistance to various diseases.

V = Verticillium wilt resistance
F = Fusarium wilt resistance
FF= Resistance to both race 1 and 2 of Fusarium wilt resistance
N = Nematode resistance
T= Tobacco mosaic resistance
A= Alternaria stem canker resistance
S= Stemphylium (gray leaf spot) resistance

Plant Habit: Another consideration is whether the tomato variety you choose is determinate or indeterminate in growth habit. Determinate (D) tomato plants grow to a certain height and then stop. They also flower and set all their fruit within a relatively short period. This is an advantage if the tomatoes are being grown primarily for canning purposes. Indeterminate tomato plants grow, flower, and set fruit over the entire growing season.

Recommended Varieties

There are probably more tomato varieties available to the home gardener than any other garden vegetable. A few will be named here, but it’s worthwhile to talk with other local gardeners to find out which ones do well in our area or just experiment by trying one or two new varieties each year. When choosing varieties, keep in mind that different varieties have different ripening periods.

Small Fruit

Large Fruit

Indeterminate

(Staking)

Red Cherry

Sweet Chelsea

Sweet 100

Sweet Million

Floradel

Tropic

Manalucie

Better Boy

Bonnie Best

Manapal

Bragger

Determinate

(Bush-type to semi-vining)

Floragold

Florida Basket

Florida Lanai

Florida Petite

Patio

Cherry Grande

Castlette

Roma

San Marzano

Micro-Tom

Walter

Suncoast

Floramerica

Flora-dade

Duke

Sunny

Solar Set

Celebrity

Extra-large varieties: Abe Lincoln, Beefmaster, Beefsteak, Bragger, Giant Belgium, Holmes Mexican, Mortgage Lifter, Giant Oxheart, Ponderosa and Wolford’s Wonder. Delicious holds the state record.

Others: Champion, Big Boy, Hayslip, Horizon, Homestead, Oxheart, Stakeless, Four-way hybrid, Jubilee, Sun Ray (yellow), Pirate.

Planting Information

Tomatoes may be started by planting seeds or by planting transplant seedlings. Suckers can also be used.

When purchasing tomato transplants, choose those with straight, sturdy stems about the thickness of a pencil. They should have 4 to 6 young true leaves, no blossoms or fruit, and be free of insect pests and diseases. Plants in individual containers or cell packs experience little or no transplant shock and become established quickly.

Producing Transplants

With proper care, well rooted, sturdy, 4 to 5 inch high tomato plants can be produced in 4 to 6 weeks. Plants can be grown in plant beds, peat pots or peat pellets, or containers such as wooden flats, metal pans, plastic "cell-paks", and milk cartons, or in hotbeds, coldframes or outdoor seedbeds.

How to grow transplants:

Ensure that your growing container has holes in the bottom for good drainage. It is best to start with a clean container. If possible, sterilize with a dilute bleach solution. Rinse thoroughly and allow to dry.
Fill your container with a good, high-quality potting mix/media. Do not use garden soil.
Purchase fresh seed. Expired seed may result in poor germination.
Sow seeds by scattering them over a smooth, firm, moist surface and then lightly cover with potting mix. An alternative method is to place the seed in a ¼-inch deep groove or hole at 2 to 3 inch intervals and cover with potting mix.
Water
Keep containers moist and in a warm place. Tomato seedlings need lots of light to prevent them from becoming leggy. Place your seedlings in a sunny window or in a greenhouse.
Thin plants to 2 to 3 inches apart when they are one inch high.
Before setting outdoors, harden off the seedlings by placing them in the outdoor environment while they are still in the containers.

Soil Preparation

Liming: The best soil pH for tomatoes is 6.2 to 6.5. Lime is needed if pH is less that 6.0. Three to 5 pounds of dolomitic limestone per 100 square feet applied 3 months prior to planting will usually be enough. If the pH is normal, but calcium level is low, apply gypsum at the rate of 1 lb/100 sq. ft.

If pH is 6.5 or higher, minor plant foods such as iron and manganese should be applied to either soil or foliage. Applications of manures and other organic fertilizers provide micronutrients also.

Ferilization: For every 100 square feet of most irrigated soils, about 10 pounds of 6-8-8 or similar fertilizer will be needed during the life of the tomatoes. One-half should be applied at planting time, placed in 2 bands each located slightly below and 2 to 3 inches to the side of the row. Part of the remaining ½ should be applied as a side dressing 3 weeks after planting. The rest should be added later at 7 to 10 day intervals. Adequate irrigation is necessary to get full benefit from the fertilizer.

If chicken manure or compost is used, broadcast and mix well into the soil 2 to 3 weeks prior to planting. Apply up to 100 pounds per 100 square feet. Then at planting time, make side band applications of low nitrogen inorganic fertilizer (for example, use one quart of 4-8-8 per 50 linear feet of row).

Compost and well-rotted, aged manure can be placed in the transplant hole, then mixed with the soil. A mixture of 2 pounds of composted yard waste plus 2 pounds of poultry manure makes a good transplant hole amendment.

Setting the Plant

Tomato plants are easily injured or even killed by frost. In the spring, they should be set in the garden as soon as frost danger has passed. They should be set early enough in the fall to produce a crop before danger of frost.

The recommended planting dates for North Florida are:

Spring: February through April
Fall: August

Transplant soon after a rain, when cloudy, or in late afternoon. Keep roots moist and undamaged. Set the plants only slightly deeper than they grow in the flat. Place the plants far enough apart to ensure good air circulation at their mature height. Crowded plants are more susceptible to diseases.

A starter solution of 1 to 2 tablespoons of 6-8-6, 4-8-8, 6-6-6 or similar analysis fertilizer per 1 gallon of water will get plants off to a fast start. Pour 1 pint around the base of each plant. Protect the plant by shading for 2 to 4 days after transplanting.

Care

Mulching: A material such as straw, leaves, dried lawn clippings, or plastic that is placed on the soil around the plant is a mulch. It conserves soil moisture, holds down weeds, keeps fertilizer from leaching, and keeps fruits from rotting on the soil.

Staking and Pruning: Staking will help to keep fruit off the ground and help to conserve space. One method of staking is to drive a 6-foot stake into the soil 3 to 4 inches from each plant, preferably before the plant is set. As the plant grows, tie it to the stake with string 4 to 6 times during the season. Make the ties just below the fruit clusters. Old stockings make great ties. Tomato cages are quite popular, and last a long time.

Suckering is the practice of removing the side branches as they emerge. This reduces the number of fruit, but causes those produced to be larger and easier to find. Leave 2 to 3 main stems to develop canopy and fruit.

Watering: Tomatoes need about 1-2 inches of water per week. If rainfall is not enough, water plants thoroughly once a week. Heavy soakings once a week are better than many light sprinklings. More frequent watering may be needed in sandy soils, especially in the first week plants are set. Include a lot of organics in your soil to help absorb and hold water. Once plants become loaded with tomatoes, more frequent irrigation is needed to prevent blossom end rot.

Weed Control: For the home gardener, the best means of controlling weeds is by cultivation. This can be done by hand or with a hoe or cultivator. Mulching also helps to keep weeds down.

Common Tomato Problems

Why have my tomatoes stopped bearing fruit? Pollination is necessary for fruit formation. Tomato blossoms are perfect flowers, containing both male and female reproductive parts and are capable of pollinating themselves. A physical means such as wind however, is needed to move the pollen. Pollination occurs within a narrow temperature range. An ideal night temperature is between 60 and 70 degrees. As night temperatures approach the mid-seventies in the summer, plants continue to flower, but cannot pollinate properly. So, it’s the hot nights that stop the plant's summer fruit production.

Even with optimal environmental conditions, tomatoes may have difficulty setting fruit when excessive nitrogen fertilizers are used. With high nitrogen, the plant becomes overly vegetative and will not produce flowers necessary for fruit production.

According to Dan Mullins, there are some exceptions. Some of the “hot set” varieties fruit somewhat longer than the standard types. The small fruited, or cherry, tomatoes continue fruiting to some degree throughout the summer and Chelsea, yielding an intermediate sized fruit, bears long into the summer.

My tomato leaves have curled up, what’s the problem? Tomatoes can develop a disorder called a “physiologic leaf roll.” It causes the lower leaves to roll upward and become thick and leathery. This disorder is usually associated with heavy applications of nitrogen fertilizers, root pruning (digging too close to the roots) and pruning of the tomato plant. While it looks disturbing, physiologic leaf roll does not reduce plant growth or yield. Interestingly, even if all cultural practices are corrected, the leaves will continue to stay rolled.

Why is my tomato rotting on the bottom? Blossom end rot is due to a shortage of calcium in the fruit. As the fruit enlarges, the plant’s water need increases. If the plant doesn’t receive adequate water or if there are soil moisture fluctuations, plant growth slows and nutrient uptake is reduced. In addition, because the nutrient calcium is carried in the plant’s water stream, those plant parts that are transpiring the most (the older, larger leaves) will receive the calcium. Developing fruit is the least likely to receive the calcium it needs resulting in a typically dark, shriveled lesion always at the blossom end of the fruit.

To avoid blossom end rot, avoid applying nitrogen in the ammonium form since it appears to negatively affect calcium uptake. Also, ensure that the plant receives adequate and consistent water. Timely and repeated spraying of tomato fruit and foliage with a calcium chloride solution may be beneficial.

What’s causing my tomatoes to crack? There are two types of growth cracks that will occur at the stem end of the tomato: concentric and radial. Concentric cracking will produce circular cracks around the stem end of the fruit. Radial cracks spread outward from the stem end. Cracks typically appear as the fruit enlarges and matures. Cracks are the result of extremely rapid fruit growth. This rapid fruit growth may be brought on by periods of abundant rain, especially after a dry period. Cultivars vary in their susceptibility to cracking. Very susceptible cultivars will crack when green. The earlier the crack develops, the deeper the cracks will become.

Proper plant nutrition and consistent, adequate irrigation will reduce the likelihood of cracks.

Why are my tomatoes puffy and malformed? This is a condition known as “catfacing.” The affected fruits are puckered with swollen projections and/or can have deep cavities in the fruit. The cause is the abnormal development of the flower. Some conditions that negatively affect flower development are extreme cold or heat, drought, improper fertilization and/or exposure to herbicides.

There is no control of catfacing other than to follow proper cultural techniques and keep the herbicides away from tomato flowers.

One day my tomato plant was beautiful and full of fruit and the next it was totally wilted even though I’ve watered it, what’s wrong? This is where is gets tough trying to make a good diagnosis. Many pathogens cause wilting.

One wilt disorder is caused by bacteria. It causes a rapid collapse and death of the entire plant. It is most severe in moist, warm, high pH and low fertility soils.

To make the diagnosis, cut through the stem near the ground. The center of the stem (pith) will be dark and water-soaked. Suspend the stem in a glass of water. If it is a bacterial wilt, white milky ooze will appear within an hour.

If you have tomato problems, you might want to peruse the University of Florida’s Tomato Scouting Guide available at http://ftsg.ifas.ufl.edu/index.htm. It has excellent pictures and a key to help you make your own diagnosis.