Drought's effect on tomatoes

7/28/2012

We have received a lot of calls from readers with questions on tomatoes and the drought conditions we are experiencing in Lucas County. Some of the most obvious issues we see with tomatoes during this extreme weather are leaves curling, blossom end rot, growth cracks, and sun scald.

Tomato physiologic leaf curl is a symptom of water stress where the leaf curls around into itself on the plant. This is usually caused by lack of moisture and even after watering, the curl is irreversible. In severe conditions, the entire plant may exhibit leaf curl, growth, or yield. Some varieties exhibit these symptoms more than others.

Blossom end rot appears when a plant is experiencing a lack of calcium uptake. The bottom of the fruit develops a black or tan lesion when the fruit is 1/3 to 1/2 grown. While this is unsightly, the major problem is that it weakens the skin of the fruit, allowing other fungi or bacteria to grow. These pathogens may result in further decay of the fruit. This defect is a result of soil moisture fluctuations alternating between rain, high heat, and drought conditions, preventing the plant from receiving the necessary calcium. One way to manage this disease is to maintain a continual level of soil moisture.

Sunscald is common in plants that suffer leaf loss, either from a leaf spot disease, or to feeding insects, plants that have been over pruned, or otherwise exposed to sun. Sun scald manifests itself with a pale yellow or white spot on the side of the fruit which receives the most sun. The pale yellow to white patch may become a flattened grayish area, and the surface dries out and becomes almost like paper. These affected areas then become prone to infections from fungi or bacteria entering the fruit. Maintenance calls for treating for diseases that affect the leaves, and to reduce direct sun exposure.

Growth cracks appear in response to rapid fruit growth. Some of these growth spurts may be a result of over abundant rain (unlikely this year in Lucas County), high temperatures, or when water appears suddenly after drought conditions.

Most of the country is suffering from the worst drought conditions since the 1950s. Following are some tips to help keep your vegetable gardens from becoming victims of drought. As we mentioned in our articles last year, when planning your gardens, it's important to make water easily accessible, so you don't have to haul it out to the "back 40."

Some options include drip irrigation, or soaker hose (water hose with punctured holes). You will use up to 60 percent less water than spraying your plants from the top with the garden hose or by using sprinklers. This technique also insures that the water is reaching the roots of the plant.

Another option is to bury gallon jugs up to the half-way mark (with holes punctured on side and bottom) between the rows of your plants. When you fill the jug, water will be released at a slower pace, maintaining a more level application of water, without experiencing evaporation.

If you have not mulched your garden at this point, mulching vegetable plants one to two inches only, will help to maintain moisture requiring less watering. Critical times for irrigation by plant include:

● Broccoli, Cabbage, Cauliflower, and Lettuce -- during head development

● Corn -- silking and tasseling, ear development

● Cucumbers, Eggplant, Peppers & Melons -- fruit development

● Tomatoes -- early flowering, fruit set, and enlargement.

There will be a Food Preservation for Local Produce presentation Aug 6 from 7 to 8 p.m. at the Sylvania Branch Library Meeting Room, 6749 Monroe St., Sylvania. It is free and no registration is required.