A summer heat wave can leave flowers wilted, vegetables stressed, and garden beds bone dry in just a few days. While most gardeners know to water more during extreme heat, experts say another simple task may be more important: mulching. Heat waves can damage your garden below the surface before you even notice—and this simple step helps prevent it.
Why Mulching Is Important Before a Heat Wave
Mulch is good for more than creating pathways and making your garden beds look tidy. According to Briana Selstad Bosch, owner of Colorado-based Blossom and Branch Farm and author of The Regenerative Gardener’s Handbook, adding mulch to your yard should be at the top of your list as the weather heats up and soil dries out. “Mulching is key for keeping soil temperatures moderated and moist, which helps keep the soil life active,” she explains. “As temperatures fluctuate, it can be hard on the soil life, as unmulched soil temperature can fluctuate wildly from day to nighttime.”
How Mulch Helps Plants Thrive
Healthy soil is filled with nutrients, minerals, and microbes that support the growth of plants, and extremely hot weather can disturb that invisible but important ecosystem. “Once soil temperatures go above 80°F, microbial activity slows,” says Bosch. “Microbial activity is vital for plant performance, disease and fungus resistance, and the ability to mineralize and absorb nutrients in the soil.” This is also why adding compost to your soil is so beneficial.
What Type of Mulch to Use
There are two types of mulch: organic (plant-based, like wood chips or pine needles) and inorganic (materials like stones, shells, plastic sheeting, and landscape fabric). Bosch recommends mulching with organic matter such as pine shavings, pine needles, straw, or leaves. Spread the mulch around plants and over irrigation lines to protect the soil from temperature swings and help keep it moist.
