Tomatoes (Solanum lycopersicum) generally do well when they're grown in full sun and warm temperatures, but in very warm southern climates like that of Louisiana, tomato plants struggle to remain productive and set fruit when summer temperatures reach their peak. Louisiana's humidity doesn't help either, since tomatoes are more susceptible to disease in humid climates. The key to successfully growing tomatoes in the state lies in choosing the right varieties and timing the planting to avoid the worst of the climate's extremes.
Varieties for Louisiana
The best tomato cultivars for Louisiana include those that have been developed for both exceptional disease resistance and heat tolerance. Heat and disease tolerant varieties that do well in Louisiana include 'Heat Wave II,''Florida 91,' 'Sunchaser' and 'Sunleaper.'
In general, large beefsteak-type varieties do not produce well in Louisiana, but some varieties, including 'Beefmaster' and 'Ponderosa,' may be able to tolerate the state's climate.
Tomatoes are vulnerable to damage from freezing temperatures, so don't set new plants in the garden until all danger of frost in your area is past. However, getting plants in the ground as early as possible will give them the best chance of producing a good crop of fruit before they succumb to the summer heat.
In southern Louisiana, including New Orleans, Lake Charles and Morgan City, it's generally safe to plant tomatoes in the middle of February. A bit farther north, in Baton Rogue and Opelousas, it's best to wait until the first half of March. In central Louisiana, including Alexandria, the safe planting time falls in late March, and in the northern part of the state, including Shreveport, temperatures are likely to be too cold until early April.
Louisiana's relatively long growing season makes it possible to plant tomatoes in mid-summer for a fall harvest. When planted at this time, the plants begin to set fruit after the highest summer temperatures have passed but still have time to produce a crop before the first frosts of the fall kill the plants.
In southern Louisiana, sow seeds directly in the garden in the middle of July or transplant young plants in August. In northern Louisiana, fall tomatoes must be planted earlier to have time to produce before fall; in this part of the state, sow seeds near the end of June or set transplants in July.
Heat-tolerant varieties such as 'Spitfire,''Solar Set' and 'Solar Fire' are especially well suited to summer planting for a fall crop.