How to Protect Your Garden During a Heat Wave

By Plant 4 Good  |  July 2026

When temperatures climb toward 100°, your garden needs a little extra love, and ideally, it needs it before the heat arrives, not after. A few simple steps can mean the difference between a garden that survives a heat wave and one that struggles to recover.

Here's what to do when a heat wave is on the way.

Water deep, water early

Morning is your window. Deep, thorough watering encourages roots to grow downward, where the soil stays cooler and holds more moisture. Avoid watering in the evening as wet foliage overnight can invite fungal disease.

Mulch any bare soil

A 2–3 inch layer of mulch acts like sunscreen for your soil. It holds in moisture, moderates soil temperature, and keeps roots from cooking in the heat. If you don't have mulch on hand, even a layer of dry leaves or straw will help.

Hold off on fertilizing

It may be tempting to give your plants a boost during summer, but feeding during a heat wave actually stresses them out. Fertilizer pushes new growth, and new growth is more vulnerable to heat damage. Wait until temperatures come back down before feeding.

Harvest early and often

Tomatoes, beans, zucchini - if something looks close to ready, go ahead and pick it. Extreme heat can stop fruit set entirely and damage produce still on the vine. Harvesting frequently also keeps plants putting energy into new growth rather than ripening stressed fruit.

Don't panic when your herbs bolt

Dill and cilantro are not fans of the heat, and this time of year they will start to flower, and that's actually a good thing! Those blooms are a favorite food source for caterpillars and beneficial insects. Once the flowers fade, they'll set seed that you can collect and replant later in the season or the following year. Let them do their thing.

Your garden is more resilient than you think. A little preparation goes a long way, and paying attention to your plants during a heat wave helps you build the kind of intuition that makes you a better gardener year after year.