September 3, 2014

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Heat, drought and blossom end rot


Normally, a hot dry year would favor vegetable production as long as growers have adequate irrigation. However, when daytime temperatures inch up over 100 degrees Fahrenheit like we’ve seen several days this year, we begin to see problems with many vegetable crops.

Pollen begins to die and that affects fruit set and several disorders become apparent. One thing growers might see is blossom end rot, which is simply a rot at the blossom end of a fruit. Tomatoes usually suffer most, but eggplant, cucurbits and peppers can all succumb to the problem. It is technically caused by a calcium deficiency in the plant or the fruit. But in many cases, it’s not a lack of calcium in the soil, but rather an environmental factor that stops the plant from taking up calcium. Plants take up calcium via their transpirational system. As plants move water through the roots to the leaves and out the stomata, calcium moves into the plant. But in areas of severe drought, blossom end rot will appear because there is no water to move the calcium to the plant. To make matters worse, calcium is immobile in the plant, meaning it can’t move from an area of low demand to an area of high demand, so even temporary deficiencies can cause permanent damage.