We have had some very hot days recently! This can be quite harmful to our plants in the garden as well as our trees and shrubs.
Plant Response to Hot Weather
Wilting is occurring on many of our plants lately, especially on plants in the vegetable garden including peppers and cucumbers. These plants wilt in the heat and they look terrible, but they will be fine and still produce well. When you notice wilting on your plants, ensure that they are getting proper irrigation and are mulched properly. When plants are wilting due to heat or drought stress, they will often look much better or completely recovered in the mornings and be wilted later in the day. If the wilt lasts too long, it can lead to plant death.
Leaf scorch on trees can also show up in extremely hot weather. It can come from hot, windy days or improper irrigation. Leaf scorch is where the edges of the leaves will turn brown. It shows up as uniform brown around the entire edge or tips of the leaves. This isn’t terribly damaging to the overall growth of the plant. Leaf scorch is common in trees like maples, sycamores and oaks.
Poor Pollination
Poor pollination occurs in the vegetable garden during the heat. Even though plants are producing, tomatoes may not be ripening. When temperatures are consistently as hot as they have been, tomatoes may develop on the plant but they don’t turn red. According to Purdue University, the pigments responsible for the red color in tomatoes are not produced when the temperatures exceed 85 degrees. So, when we see long stretches of very hot weather, our tomatoes will not ripen. Also, at temperatures above 94 degrees, pollen becomes sterile, causing them to flower and not produce fruits. Give the plants some time and a little cooler weather, and they will produce plenty of fruits.
Helping Plants through Extreme Heat
There are some things you can do to help your plants get through these times of extreme heat. Ensure that your plants are receiving adequate moisture, continue to use that screwdriver method to ensure that water is necessary prior to irrigation and to ensure that you are irrigating deep enough to reach the plant roots. It is easy to overwater plants in extreme heat, so if the soil has adequate moisture, there is no need to water even when this hot. Water in the morning to avoid water loss to evaporation. It is not a recommended practice to water in the mid-afternoon, this doesn’t help cool the plants off. Maintain a correct mulch layer around plants to retain water around the plant roots and to keep the roots cool.
Also, do not fertilize plants in extreme heat. During these times plant processes will slow down and fertilizer promotes growth that the plant cannot support. Fertilizing a stressed plant will further stress it, this includes during stressful times of high temperatures. Deadheading flowers can help your plants get through the heat because they won’t be pushing energy toward flowering and seed production and can focus their energy on sustaining roots and shoots.
If you have any further questions please contact Nicole Stoner at (402) 223-1384, nstoner2@unl.edu, visit the Gage County Extension website at www.gage.unl.edu, or like my facebook page at http://www.facebook.com/NicoleStonerHorticulture and follow me on twitter @Nikki_Stoner
Nicole Stoner
Extension Educator
Gage County
August 2024