For Release July 18, 2000

Stressed Gardens Produce Stressed Vegetables

by Chuck Otte, Geary County Extension Agent

Itís bad enough that the weather has brought us all this heat and dry weather, but now itís impacting virtually all of our garden crops as well. Growing a garden in Kansas can oft times be a real challenge. But the combination of weather events leading up to the 2000 garden season have made it an even bigger challenge.

Weíll start with heat and drought stress. While irrigation will help keep your garden alive, it can not replace the kind of weather that comes along with regular rainfall. Just a little bit of drought stress at the wrong time can cause havoc with garden plants. Blossom end rot is a condition of tomatoes where the blossom end, the end opposite the stem, starts to rot. It is a non-disease condition caused by rapid growth in mid summer. It can be made worse when there excessive soil moisture fluctuation. Using mulch, and maintaining a constant soil moisture condition helps. Eventually the plant will outgrow this condition.

Soil moisture fluctuation also creates problems in most all of our vine crops. Lumpy cucumbers and zucchini result from drought stress during fruit development. Additional moisture wonít cause the skinny part of the fruit to disappear, it simply allows the rest of the fruit to develop normally. This moisture stress is also one of the causes of bitter cucumbers. When cucumbers undergo stress, they produce a couple of very bitter compounds. The compounds tend to be highest at the stem end, and just under the skin. Deep peeling will help to reduce the bitterness. The best solution is to use mulches and donít drown the plant, but keep a constant soil moisture condition.

Heat causes enough problems of itís own. Tomatoes often wonít set fruit during very hot weather. They will bloom and bloom, they just wonít set. Cooler weather will cure that problem. Fruit that is on the vine often wonít develop a good red color under high temperatures. If this is happening, just pick the fruit when it is showing some color development, bring it inside and set it on a window sill. The cooler temperatures inside your house will allow the fruit to finish developing normal colors as it ripens.

High temperatures can also cause problems with many other garden crops. Excessive heat during sweet corn pollination can cause spotty kernel set on the ear. Unfortunately, most sweet corn plants will only have one or two chances at setting a good ear. Heat at the wrong time will blast your chances which is why we often advise multiple plantings of sweet corn. Likewise, high temperatures will cause beans to bloom but not set. Theyíll usually keep blooming until temperatures cool down enough for pods to start setting on.

The warm weather also created a good opportunity for larger than normal numbers of insects to survive. Large insect populations were just waiting for your garden plants to get started. Squash bugs have caused a lot of problems much earlier than normal. Plant bugs and cucumber beetles have also been quite abundant. Corn earworm, a.k.a. tomato fruitworm, are also causing a lot of damage. Regular insecticide treatments may well be required to keep these critters under enough control to have a crop to harvest. Be careful with the insecticide Sevin, carbaryl, though. Heavy use of Sevin can cause heavy populations of spider mites to develop. Sevin does not kill spider mites, but it does kill many of the spider mite predators. This is a challenging year to be gardening, but persistence will pay off!


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