Exploring the Ozarks Outdoors: freshare.net

Hot Weather Playing Havoc in Home Gardens

By University of Arkansas

First posted on 07-19-2011

by Mary Hightower, U of A Division of Agriculture

Weeks of hot, dry weather are causing disappointment for home vegetable and fruit growers who, despite lavishing care on their plants, aren’t seeing the fruits of their labors.

“I am getting tons of calls,” said Jerri Lephiew, Ouachita County extension agent for the University of Arkansas Division of Agriculture. “Everyone’s garden is crashing. People aren’t seeing fruit setting on their plants.”

Home gardeners are lamenting the lack of tomatoes, beans, squash and okra.

Lack of fruit set can have many causes. High nighttime temperatures are a major problem. Several cities in Arkansas saw record highs this week. On Wednesday, Russellville hit 107 and Batesville 104 with lows not dipping below the mid 80s.

imageThe heat can causes the plant’s flowers drop. No flowers, no fruit.

“If nighttime temperatures don’t fall below 75 degrees Fahrenheit during flowering to early fruit development, tomatoes just won’t set fruit,” said Sherri Sanders, White County extension agent for the University of Arkansas Division of Agriculture.

“As it cools and we have three or four nice evenings, we should be seeing tomatoes set some fruit,” said Craig Andersen, extension vegetable specialist for the University of Arkansas Division of Agriculture.

The high temperatures can also have an effect on ripening. “Temperatures in excess of 110 degrees inhibit the ripening chemistry of the tomato in a similar manner to which cold temperatures damage fruit ripening,” he said. “However, there is always the alternative and that’s fried green tomatoes.”

The same goes for green beans, Andersen said. “They won’t set pods when there are high temperatures, especially high nighttime temperatures.”

“Squash is probably being affected by water and heat stress,” he said. “When it cools down a little bit, the fruit will come back.

“The okra is more perplexing,” Andersen said. “They usually take the heat quite well.”

Andersen said that in the southern part of the state: “fire ants have been attacking the flowers. They eat the okra flowers.

“There have been other problems recently like blister beetles coming out of alfalfa and soybeans and going into the garden and eating the flowers and young leaves,” he said. “This has not been a great season for gardening.”

Where blossoms have stayed aboard, pollination problems can be a factor in the lack of fruit.

If there’s no fruit set, “there may not be any pollinators,” said Jon Zawislak, extension apiculturist for the University of Arkansas Division of Agriculture.

“Tomatoes require big bees,” he said. “Because of the way tomato pollen sticks, the plant requires buzz pollination, which calls for bumble bees. Honeybees are too small to pollinate tomatoes effectively.” In buzz pollination, the bee vibrates the pollen loose.

Dan Chapman, director of the University of Arkansas’ Fruit Research Station in Clarksville, said the heat was also affecting blackberries and peaches.

“In blackberries, it’s not the female flower, but the male flower that can’t take the heat,” he said. And you have to have both to get fruit.”

“Our peach crop is down, the fruit size is down and all the growers have had problems with size and quantity too,” Chapman said. “It’s just a pitiful year.”


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