Every backyard garden needs at least one tomato plant. Sneaking tomatoes into your garden or landscape is relatively easy if you follow LSU AgCenter recommended growing practices.
Before planting, loosen the soil at least 6 inches to 8 inches and add compost, aged manure or fertilizer. Routine soil tests will identify fertilizer needs and potential soil pH adjustments. Optimum soil pH for tomatoes is between 6.0 and 7.0. In clay soils, mounding soil into rows is encouraged to help provide drainage. In sandier soils, hipping or forming rows is not necessary.
Tomatoes grow well in containers. Canvas, clay, ceramic, plastic, wood or metal containers are all acceptable, provided they have drainage holes and are at least 5 gallons in size. Container size is important because tomatoes have extensive root systems. Tomato roots quickly outgrow small containers, leaving the gardener watering the plant both morning and night. Planting tomatoes in larger containers reduces irrigation frequency. An added bonus of reducing irrigation is the likelihood of less blossom end rot. Blossom end rot is a calcium deficiency in the plant and is exhibited by blossom end of the tomato rotting. Most native soils and potting mixes contain sufficient calcium, but overwatering leachs the calcium from the soil in container-grown plants.
Spring tomatoes are planted immediately after the last frost, typically March 15 in south Louisiana and April 1 in north Louisiana. Spring tomatoes are harvested through June and sometimes later if heat-set varieties were planted. The spring season is optimum for heirloom tomatoes, hybrids and non-heat-set types. Louisiana gardeners face a potential virus termed tomato spotted wilt virus (TSWV) in the spring. The virus is spread by thrips, a tiny insect that within 10 seconds of piercing into the foliage infect a plant. If the plant is infected prior to fruit set, it will not produce fruit. If fruit has already set, the skin will show yellow halos. Insecticides are not helpful against this virus. Therefore, planting a few tomato spotted wilt virus-resistant varieties in the spring is strongly recommended as “crop insurance” for spring-planted tomatoes.
Summer and fall tomatoes are planted mid-July to late August and are harvested until the first killing freeze. High nighttime temperatures result in poor pollen set and sometimes sterilization of pollen, resulting in poor fruit set. Because nighttime temperatures during this period are often greater than 75 degrees, gardeners plant heat-set varieties.
There are literally hundreds of tomato varieties to choose from. However, good gardeners select varieties that perform well in the area where they live. The AgCenter regularly conducts spring tomato trials. All varieties in the trials were replicated at least three times with 10 to 15 plants per replication. The varieties were also randomly planted in the field using drip irrigation and plastic mulch. Tomatoes come in two types: Indeterminate tomatoes have apical meristems that terminate in a vegetative bud, allowing them to grow very tall. Determinate tomatoes are short, bushy types. Their apical meristems terminate in a flower bud.
Kathryn Fontenot is an assistant professor and extension specialist in the School of Plant, Environmental and Soil Sciences.
(This article appeared in the spring 2016 edition of Louisiana Agriculture magazine.)
Spring tomatoes are planted immediately after the last frost, typically March 15 in south Louisiana and April 1 in north Louisiana. Summer and fall tomatoes are planted mid-July to late August and are harvested until the first killing freeze. Photo by Johnny Morgan