Heat Stress and Plant Growth

Gardeners in the Southeast know from experience that summer heat can be punishing. We also know—sometimes the hard way—that it's best to avoid installing new plants or building out beds during the hottest months. Anyone who’s planted something in July only to watch it fade quickly knows the feeling (I’ve done this more than I care to admit).

In this article, I’d like to take a deeper look at why plants suffer in summer heat—what’s happening inside the plant—and what that stress is trying to tell us. Understanding the why behind heat stress can help us better care for both established plantings and any new additions, even if they go in during less-than-ideal conditions.

How Plants Grow: A Quick Primer

Before diving into heat stress, we need to briefly review three key physiological processes in plants: photosynthesis, respiration, and transpiration. These are the basic systems that drive growth and survival.