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The world is getting hotter. 100 degrees in the Arctic? Yes, that happened in June 2020.  Gardeners in zones that have never dealt with scorching temperatures must now learn how to protect garden plants during heatwaves.

Here are some tips for keeping your garden cool when the mercury rises:

Katsujiro Maekowa, Flickr, Creative Commons.

Garden Early in the Day
Pour your morning coffee and work in the garden early before the day heats up. Watering in the morning when temperatures are cooler gives plants time to absorb the water so they can stay hydrated throughout the day. 

RainReady Home, Flickr, Creative Commons.

Keep Plants and Soil Cool
Keep yourself, your plants, and the soil cool and hydrated. Pay attention to any water restrictions in your growing zone that may be in place during heatwaves. Conserve water by harvesting rainwater in cisterns and water efficiently using drip irrigation or soaker hoses.

Flickr, Creative Commons.

Water Deeply
Water deeply at least six inches down to encourage deep roots. If watering by hand, water close to the soil under the plant without touching the leaves, as water on leaves can promote fungus. Water vegetables at least two to three times a week during severely hot weather.

Containers and hanging baskets need more frequent watering as they dry out faster than plants in the ground. Place a finger into the soil, and if it isn’t moist up to a knuckle, the plant needs water. Plants will tell you when they need water—they wilt. If you see drooping leaves, they need a drink. 

Use Mulch
Not only does mulch help maintain hydration and limit weeds, but it also slows down evaporation to keep the soil cooler. Be sure to refresh mulch one to two times throughout the season.

Ivan Radic, Flickr, Creative Commons.

Maximize Shade and Airflow
Use shade cloth or protective row covers to protect plants and help cool the soil. The temperature under the cloth can be 10 degrees lower. Do not lay the fabric directly on the plants, as they need adequate air circulation.

Place plants in spots that catch the prevailing winds to maintain airflow and keep them cool. Locate tender new transplants within the shade cover of taller plants.

Jonathan Kemper, Unsplash.

Don’t Stress Plants
Avoid anything that might stress a plant in extreme heat, such as transplanting, pruning or fertilizing.

Rick Orchard, Flickr, Creative Commons.

Keep the Garden Weeded
Keep the garden weeded as weeds compete with other plants for water and nutrients.

Stephan Eicksche, Unsplash.

Swap the Lawn for a Meadow
A 10’x10′ patch of lawn requires over 62 gallons of water. Consider a wildflower takeover: swap your water-guzzling lawn for a more drought and heat-tolerant wildflower meadow that supports pollinators and never needs weeding. If maintaining a lawn, keep turf at least three inches tall. 

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Select Heat-Tolerant Plants
Heat-tolerant and drought-tolerant aren’t the same thing. Choose heat-loving plants adapted for your growing zone, whether dry or humid.

Andy Makely, Unsplash.

Tropical plants like hot, humid climates, while drought-tolerant, xeriscaping plants thrive in areas with high heat and little rainfall. Many of each type can endure heat waves.

Cale Crunchy, Unsplash.

Some heat-resistant plants tolerate both dry and humid conditions—not just surviving in long periods of heat, but thriving in it: 

• Warm-season ornamental grasses
• Phlox
• Heucherellas
• Daylilies
• Amsonia
• Artemisia
• Lantana
• Geranium
• Coreopsis
• Impatiens
• Morning Glory
• Cosmos
• Marigold
• Vinca
• Sunflower
• Dahlia
• Dusty Miller
• Euphorbia
• Salvia
• Sedums
• Zinnia

Kaique Rocha, Pexels.

Monitor Plants for Signs of Heat Exhaustion
Check plant leaves frequently for signs of heat damage. Just like people, plants can succumb to heat exhaustion.