A summer heatwave 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. Heatwaves can damage your garden below the surface before you even notice – and this simple step helps prevent it.

Why mulching is important during a heatwave

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 garden 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."

simple image of a spade among a pile of woodchipspinterest
Catherine Falls Commercial//Getty Images

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 27°C, microbial activity slows," says Briana. "Microbial activity is vital for plant performance, disease and fungus resistance, and the ability to mineralise and absorb nutrients in the soil."

What to Read Next

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 chippings or pine needles) and inorganic (materials like stones, shells, plastic sheeting and landscape fabric). Brian recommends mulching with organic matter such as 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.

Garden decor
Headshot of Lisa Cericola
Lisa Cericola
Freelance Writer

Lisa Cericola (she/her) is a writer and editor who specializes in travel, food, and culture. A South Florida native, Lisa lived in New York City for 15 years and now resides in beautiful Birmingham, Alabama. She has been an editor at Southern Living and Food Network Magazine and writes for numerous publications including Garden & Gun and Late Checkout. When she’s not working on a story, or planning her next trip, Lisa is likely making and selling small-batch olive oil granola at her local farmers market.