10 Tips to Help Plants Survive Summer Heat

Even waterwise plants get stressed when exposed to high heat, dry air and wind. Many Southwestern plants can survive hot temperatures because they’re native to the low desert. But in some areas such as the mountains and high deserts, native plants are a little more winter hardy and a little less heat tolerant.

chocolate flower blooms
Chocolate flower (Berlandiera lyrata) blooms are perkiest in early morning but tend to wilt late in the day. No need to water or worry.

Even in the hottest Southwest and West climates, plants can need extra attention when temperatures soar. Here are 10 tips for helping plants survive the heat of summer.

Tip No. 1. Use drip irrigation.

You save water because it can’t evaporate as rapidly as it can if in the air, and the water seeps slowly down to the roots of a plant. This helps cool roots as well as hydrate them.

drip irrigation and straw on cucumber seedling
Drip irrigation is the only way to go for water savings and for keeping plants hydrated on hot days.

Tip No. 2. Use mulch.

Something as simple as straw spread out on the dirt helps keep air from rapidly evaporating water, but still allows oxygen to reach soil and roots. Piling the straw or other organic mulch two to three inches high helps even more.

straw mulch container tomato
Happy new tomato fruit with straw mulch in a container.

Tip No. 3. Try to get your plants established before summer heat ramps up.

Even heat-loving plants can wilt when temperatures soar. Still, recognize that wilting from sun can be temporary. The bigger the plant’s leaves, the more quickly the plant transpirates, which is the process of water evaporation through leaves. That’s why many succulents and xeric plants have small foliage. So don’t panic, but don’t completely discount it. Increase drip time on hot and windy days.

Tip No. 4. Water in the morning if at all possible.

This is a great water-saving strategy and helps prevent heat stress to plants. If the roots already have access to water, they can begin sending the water up through stems and leaves to keep the plant nourished. For most plants, regular, but spaced, deep watering always beats out frequent light watering (which leaves moisture close to the surface and can restrict root growth).

Tip No. 5. Check on your plants.

If you can’t check them during the day, do so as soon as you get home. It’s OK to water plants lightly in late afternoon to help cool them down.

xeric garden summer heat
Walking around your garden helps you spot heat stress and pest damage.

Tip No. 6. Use one plant as a benchmark.

For example, zucchini leaves are large, and if they’re wilting, you can prevent heat or drought damage to other plants nearby with a cool drink of water or some shade.

Tip No. 7. Shade plants.

New or damaged plants might need temporary shade to build up resistance to heat. Direct sun can burn leaves just like it can burn your skin. So make sure even an established plant is in the right location for sun and summer exposure and if not, try temporary shade.

cloth shade for plants.
It’s not pretty, but it’s clever. Tim built this removable shade out of landscape fabric, PVC and conduit.

Tip No. 8. Use containers.

Containers offer you the most opportunity to shade plants on hot days. Although soil in containers warms faster, containers also can cool more quickly. Most of all, it’s easy to move all but the largest into shade temporarily. You can mulch the top of the soil in a container, too.

containers on patio
Got containers? If you see a plant might be getting too hot, move it into afternoon shade. The white bucket in one container helped shade a new cherry tomato from sun and wind.

Tip No. 9. Avoid fertilizing plants during the heat of the day.

Plants should be perky and healthy before soaking up fertilizer. And the fertilizer needs to mix with plenty of water. It’s best to do this task before mid-day heat kicks in.

Tip No. 10. Control weeds.

Ha, there’s an impossible goal around here. And I know there are people who embrace weeds. I tolerate them only because I can’t keep up. But we’re really vigilant about keeping weeds off of or out from under plants. That’s especially true in the vegetable garden. Mulching can help control weeds.

field bindweed
Bindweed wraps around the base and stems of plants, weakening them. All weeds compete with garden plants for water.

Bonus tip.

Finally, if you keep potted plants, including cacti, inside during the winter, you need to protect them as they adapt to being outside. That’s true even for sun lovers. Harden the plant off if you can. If the plant is too heavy to bring in and out all day (or you have 30 of them, like we do), at least start it outside on a cooler, cloudier day.

Cacti under shade cloth
Succulents under the shade cloth. Yes, even some cacti can get too much sun. Containers allow these to survive winter inside and summer out in the heat.