(Radio Iowa) – July is typically Iowa’s hottest month of the year, and while August will arrive later this week, it may be equally as steamy, which can mean trouble for Iowans with vegetable gardens and fruit crops. Aaron Steil, a consumer horticulture specialist at the Iowa State University Extension, says we’ve had some very hot weeks already this summer and problems begin to develop when temperatures go above 90 during the day, and stay around 75 at night. “When we start getting really warm, especially in the vegetable garden, we’re going to start to see things like slow ripening on tomatoes,” Steil says. “You may be looking at your garden and seeing all these green tomatoes and thinking that they’re being very slow to turn red, and that’s very possible in really hot weather.”

Flavor is also affected by hot weather. Cucumbers may taste bitter, and crops like melons and carrots may have reduced sweetness. Temperatures above 85-degrees can delay ripening in multiple types of vegetables. “Sometimes we see a decrease in the yield or fruit set,” Steil says, “so we’ll see flowers drop or really poor pollination, and that can lead to lower yields, but it can also lead to weird-shaped cucumbers or squash.” Some areas of Iowa remain dry, but most have gotten very healthy rains this month. Steil says if you’ve had a lot of heavy rain, it may cause a calcium deficiency in the soil which can lead to blossom end rot, where a big, dark splotch appears on tomatoes.

“Inconsistent moisture doesn’t allow for that calcium to get to that really fast-developing fruit very well and it causes cell walls to break down and then secondary infections pop in,” Steil says. “We see it often on tomatoes, but we can also see it on things like summer squash, peppers and even things like eggplants.” If that rotten spot appears, he recommends plucking and chucking that fruit, which should help the plant produce a new flower. Steil says many Iowa gardeners are having a decent summer, with a good mix of ample sunshine and rain showers. “Many of the plants we grow in our vegetable gardens like it on the warm side, and they always need good amounts of water to produce well,” Steil says. “Sometimes when we get these really big gully washers, we’re more likely to see things like cracking on tomatoes because those tomatoes get so much water so quickly, it actually breaks the skin.” They’re still good to eat, he says, they just may not be as pretty.

If you’re in one of the dry areas, Steil says deep watering once a week can help reduce plant stress and promote deep, resilient roots. Also, he says to add a layer of mulch to help lower soil temperatures and reduce water lost to evaporation.