Garden Column for the Salisbury Post

Darrell Blackwelder

May 8, 2006

     Tomatoes are the favorite vegetable grown in Rowan County and many home gardeners have already planted their early crop. I usually receive an abundance of questions as soon as the plant begins to set fruit. Below are a few mistakes by home gardeners. There is still time this season to remedy some of these problems in the quest for the perfect tomato.

     1. Many home gardeners usually don't test their soil.  This leads to guessing as to what type of fertilizers are needed for optimum growth. Many tend to over‑lime and fail to add needed nutrients for optimum growth.

     2. Improper fertilization.  Tomatoes are extremely heavy feeders and need a constant source of fertilizer.  Most fail to side dress with extra fertilizer after the plants start to set fruit. Fertilize every four weeks with two tablespoons of 10‑10‑10 per plant to maintain vigor and produce large fruit.

     3. Too much shade. Tomatoes need full sunlight most of the day. Partial shade from trees or buildings limits production and quality of fruit. Plants become dark green, tall and spindly.  Plants in this situation produce few fruit.

     4. Wrong variety for this area. Many of the older varieties have no resistance to fungal and bacterial diseases. Before purchasing seed or plants, make sure the plants are VFNT Tomatoes: V (verticillium), F(fuscarium), N(nematode), and T(tobacco mosaic) resistant.  For example, Big Boy, German Johnson and Fantastic are two varieties that have no disease resistance and can be difficult to grow.

     5. Home gardeners fail to spray with fungicides. Tomatoes are susceptible to a wide host range of both fungi and bacterial diseases. Fungal diseases during damp, humid weather can defoliate plants within days producing small, poor quality fruit.

Maneb, zineb, Bravo, sulfur, and copper sprays are just a few fungicides home gardener can use to control foliar diseases.

     6. Incorrect irrigation or watering practices.  Blossom end rot is a calcium deficiency which is aggravated by too little or too much water. Blossom end rot is characterized by black rotten spots on the blossom end of the tomato just before ripening. These plants require even moisture during periods of drought.  Drip systems or soaker hoses coupled with a layer of mulch aids in retention of even moisture. Lime is the source of calcium which needs to be added to the soil before planting.

     7. Planting only one variety. Many are surprised as to how well newer varieties perform and taste.  Newer varieties are not only disease and heat resistant, but actually have good flavor. Plant your favorite, but always try a few new varieties each year.

     8. Improper insect control.  Aphids are usually the first insect to attack tomatoes and most use Sevin for control.  Sevin will not control aphids.  Insects can be a real pain late in the season.  Most are not prepared to spray during late summer and are eaten alive by fruit worms.

Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension in Rowan County.