Troubling Tomatoes

Gardening by the Yard : Episode GBY-907 -- More Projects »
Click here to view a larger image.

Are your plants failing to set fruit? Read on.

Master gardener Paul James tackles one of summer's most puzzling garden problems: why don't my tomato plants set fruit? A tomato plant's failure to set fruit can be caused by several things, but there are some common causes.

  • Hot weather may be the culprit behind fruitless plants. Although tomatoes are true warm-season crops and need plenty of sunshine to maximize fruit production, temperatures above 85 degrees F may cause them to stop flowering. Without flowers, there won't be any fruit.

  • Blossom drop, where flowers form but drop prematurely, is another reason why tomato plants might not fruit. Blossom drop can be caused by the weather--rainy and cool or hot and dry--or a magnesium deficiency, which can be corrected by either spraying the plant with a seaweed extract or by applying Epsom salts to the soil at a rate of two to three tablespoons per plant. Too much high-nitrogen fertilizer is another fairly common problem, which leads to lots of foliage, but little or no fruit.

  • Remember, too, that there are two types of tomatoes. Indeterminate types can grow quite tall and produce fruit over a long period of time, and determinate types are much shorter and produce fruit over a much shorter period of time.

    "Thankfully, the factors that affect a tomato's ability to set fruit are fairly easy to control, with the exception of weather," says James. "And if you provide a tomato plant with everything it needs, such as good soil enriched with plenty of compost and aged manure, lots of sun, and a nice layer of organic mulch, you should have a substantial harvest and plenty of BLTs!"

    Find out more:

    The Great Tomato Race
    Growing Good-Looking Tomatoes
    Preventing Plant Disease
    Gardening Basics