Help Your Garden Survive the Summer Heat

One thing is for certain: Texas weather is unpredictable. Snow one month, rain the next, and triple-digit heat the month after that.

When the temperature suddenly jumps above 100 degrees with little notice, keeping your garden happy, healthy, and productive can be a big challenge.

If you’re new to Texas or worried about your garden during an unexpected heat spell, here are 7 ways to help your garden survive and thrive.

1. Increase watering frequency.

The general rule for watering a garden under normal circumstances is to give plants one inch of water per week whether this comes from rain or supplemental watering.

Once temperatures reach 100 degrees, however, certain plants such as vegetables, bedding annuals, and plants in containers will require daily watering.

When in doubt, it’s better to water than not water when temperatures are consistently in the triple-digits.

2. Water deeply in the morning.

This is a practice that you should always adopt no matter how hot it is outside, but it’s especially important when the temperature rises above 100.

Deep, morning watering is important for four reasons:

  1. It prevents loss of water through evaporation. If you water later in the day most of the water will evaporate from the hot soil before plant roots get a chance to absorb it.
  2. By mid-day, plants are stressed. Stressed plants can’t use water and nutrients as effectively as rested, happy plants can in the morning.
  3. Deep watering encourages deeper root systems. Frequent shallow waterings encourage plant roots to stay at the surface of the soil where they are exposed to higher temperatures and fluctuations in moisture.
  4. Watering close to sundown or after dark increases the chances of fungal diseases because water droplets on leaves are slower to evaporate.

3. Consider shade cloth.

For plants that are sensitive to heat or seem to be wilting faster than other plants, shade cloth is an effective solution. Shade cloth lets only a certain percentage of sunlight through to the plants below. This helps to reduce ambient temperatures by as much as 15 degrees.

To get maximum temperature reduction but still provide plants with enough sunlight to grow well, look for a 40% to 50% shade cloth.

4. Reduce fertilizer.

The consistent application of a balanced, organic fertilizer is the key to strong production from your vegetable garden, but fertilizer can place unnecessary stress on plants when temperatures are very high.

Under stressful conditions, plants need to allocate as many resources as possible towards survival. Fertilizer tells the plant to put on new growth, tying up valuable resources in the process.

When the forecast calls for consistent triple-digit temps, reduce the frequency of fertilizer application, or suspend it entirely until temperatures drop back into the low 90s.

5. Add another layer of mulch.

Mulch is a multitasking superhero in the garden. Mulch is fantastic because it…

  • Conserves moisture
  • Cools the soil
  • Prevents disease
  • Suppresses weeds
  • Reduces pest pressure
  • And adds nutrient-rich humus to the soil as it breaks down

If you still haven’t mulched your garden by the time high summer temperatures arrive, it should be the very first thing that you do.

If you’ve already mulched your garden (congrats!) then take a moment to measure its depth. To maximize weed suppression and soil moisture retention, mulch should be applied to a depth of at least three inches.

We recommend hardwood mulch because it is long-lasting but still lets the soil “breathe”. Plus, it’s economical and easy to find.

6. Move containers to shadier locations.

When high temperatures arrive, you might consider moving containers out of any locations that receive harsh, direct sun in the late afternoon. The ideal location for containers in hot weather is a location that receives morning sun and afternoon shade.

Containers will also benefit from a layer of mulch on the soil surface to reduce moisture evaporation and keep the soil cool.

7. Check for plants that are still wilted after sundown.

Some plants will naturally wilt a bit in the middle of the day but perk up after sundown. Sweet potato vine and summer squash are two good examples.

There is cause for concern, however, if a plant wilts during the day but doesn’t perk back up after sundown. This is a good indication that the wilting is a sign of more severe stress.

Once the sun goes down, check for any plants that are still wilted and give them a long soak.

Source – Callie Works-Leary

Founder of The Dallas Garden School, Callie has 15 years of gardening experience and horticulture education. She specializes in growing food, small-space gardening, managing community gardens, and plant propagation. She has an MBA from Southern Methodist University, a joint Business-Spanish degree from Skidmore College, and served as a horticulture intern for the Dallas Arboretum & Botanical Gardens. Callie is a member of the Native Plant Society of Texas, The Herb Society of America, the National Garden Bureau, and is a Certified Texas Master Gardener.