FROM PLANT TO PLATE

Blossom-end rot prevalent in area

8/13/2011

It has been a busy summer in the Lucas County OSU Extension office thanks to some unpredictable weather. We have gone from excess rain in the spring, to drought and high temperatures across June and July. August seems to be starting out better, so keep your fingers crossed for cooler temperatures and rain.

One of the many samples brought into the office recently for diagnosis and identification is blossom-end rot of tomato, pepper, and eggplant. We also are seeing this in our office garden at 5526 West Bancroft St.

On tomatoes and eggplants, blossom-end rot usually begins as a small water-soaked area at the blossom end of the fruit. This may appear while the fruit is green or during ripening. As the lesion develops, it enlarges, becomes sunken and turns black and leathery. In severe cases, it might cover the lower half of the fruit, becoming flat or concave. On peppers, the affected area appears tan, and is sometimes mistaken for sunscald, which is white. Secondary molds often colonize the affected area, resulting in a dark brown or black appearance. Blossom-end rot also occurs on the sides of the pepper fruit near the blossom end.

Blossom-end rot is not caused by a parasitic organism but is a physiologic disorder associated with a low concentration of calcium in the fruit. Calcium is required in relatively large concentrations for normal cell growth with tomatoes.

To help increase and maintain calcium maintain the soil pH around 6.5. You can call our office for information on soil testing. Also, putting down lime and using nitrate nitrogen fertilizer will supply calcium.

Avoid drought stress and wide fluctuations in soil moisture by using mulches and irrigation. Plants generally need about one inch of water per week from rain or irrigation for proper growth and development.

The other problem that northwest Ohio gardeners are having with tomatoes is blossom drop. Unfortunately, blossom drop is caused by high temperatures, and our corner of the state has had plenty of heat this summer.

Our horticulturists and master gardener volunteers also have received questions from gardeners about small green peppers.

Extremely high temperatures (90 degrees or above) during flowering often results in blossom drop. Peppers that set when temperatures average above 80 degrees might be small and poorly shaped due to heat injury to the blossoms.

Our master gardener volunteers do some of the research for the issues we've been featuring in this column. If you would like to learn more about becoming an OSU Extension master gardener volunteer, classes are forming for 2012.

There will be informational meetings at 2 p.m. and 7 p.m. Aug. 22 in the Conference Center at Toledo Botanical Garden, 5403 Elmer Drive. If you are interested in joining call 419-578-6783, or email northrup.10@cfaes.osu.edu to reserve a space.

Lee Richter is a program assistant with OSU Extension Lucas County. If you have questions, call the OSU Extension Master Gardener Volunteer Horticultural Hotline at 419-578-6783. Volunteers are on hand Monday, Wednesday, and Friday from 10 a.m. to 1 p.m. Questions also may be emailed to mghotline @ag.osu.edu and possibly answered in a future Plant to Plate column.