Managing Heat Stress in Plants

“I have no doubt that the heat is killing me, but what about my plants?”

“Is it hot enough for ya?”  If you feel like socking the next person who starts conversations with reference to our current weather pattern, you’re not alone. When access to a free sauna experience can be had by walking outside, by most accounts, it is summer in the south. And heat stress impacts everything that can’t find a place to cool off.

For our plants, there aren’t many options since moving to a shadier place or an air conditioned building requires a mobility feature they don’t have. Therefore, when plants wilt, drop leaves, or shed blossoms, heat stress could be the culprit. During high temperatures such as those we’ve experienced in the last couple of weeks, tomatoes, squash, peppers, melons, cucumbers, pumpkins and beans will drop blossoms, while broccoli and other cool-loving crops will bolt and figuratively melt away.

heat stress in plants

Courtesy of GardenVigor.com

Some varieties of ornamental and edible plants exhibit leaves that cup (curl) up, which if not caused by insect damage, is another sign of heat stress in plants.

To reduce the impact of excessive heat, make sure plants are watered on a regular basis.   Therefore monitor plants, especially those in containers, and supply water when rainfall isn’t sufficient. All plants, whether in-ground, raised beds, or containers, benefit from a layer of mulch on soil surface. Mulch not only keeps soil and roots a few degrees cooler than unmulched subjects, it helps conserve soil moisture. Mixing humus in ornamental or vegetable beds is another practice that aids in water penetration of clay soils, but is best done prior to planting to avoid damaging roots.

By Sallie Lee, Urban Regional Extension Agent, Alabama Cooperative Extension System.  Contact Sallie at leesall@aces.edu.


The Alabama Cooperative Extension System (ACES) operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities. ACES is committed to affirmative action, equal opportunity and the diversity of its workforce.  Educational programs of ACES serve all people regardless of race, color, age, sex, religion, disability, sexual orientation, or national origin.

Alabama Extension

The Alabama Cooperative Extension System operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities and answers home-gardeners' questions each week on Birmingham Gardening Today.

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