How to Help Your Garden Survive a Heat Wave
See what to do to help keep your plants thriving in summer’s heat and how to tell if sunburned ones can be saved.
Most summers have a period of abnormally high temperatures that can be highly stressful for plants, resulting in wilting, sunburn and even death. Heat waves don’t arrive without warning, and today’s weather technology gives us several days in which to prepare plants for an onslaught of intense heat.
Plants in containers are most susceptible to extreme heat, as the air temperatures can cook the roots as well as the tops. Shallow-rooted plants are particularly sensitive to the effects of a heat wave, while most succulents are fairly tolerant.
Thankfully, there are methods we can use to moderate the damaging effects of a heat wave. Here are five ways to help your plants survive the heat.
1. Give your plants extra water. High temperatures increase the rate that water is lost to the atmosphere from a plant’s leaves, resulting in wilting and sunburn damage. You’ll need to increase the amount of supplemental irrigation that they receive. It’s best to do this the day before the heat wave arrives. The best time to water plants is early in the morning, when temperatures are lower, which will help carry them through the day.
2. Provide temporary shade. On a hot summer’s day, we all look for a shady spot where temperatures are a few degrees lower. Unfortunately, plants can’t move toward the shade, but we can bring it to them. Nurseries and big-box stores carry landscape burlap and shade cloth, which can be placed on top of plants to screen them from the sun. Other temporary shade methods include using a portable shade canopy to shield an area of the garden from the sun. Even a single patio chair can protect a low-growing plant.
3. Mulch. Hot temperatures don’t affect just the parts of the plant that are above the ground; they also impact the roots. Adding a layer of mulch around trees, shrubs and ground covers will help keep the soil several degrees cooler while preventing it from drying out.
4. Avoid pruning. It’s tempting to prune away sunburned growth, as it isn’t attractive, but put away those pruners. Although the outer foliage may be damaged, it’s protecting the interior of the plant by providing shade. Wait to prune away sun-damaged growth until temperatures return to normal. For extra safety, wait until summer is almost over before pruning away in case of the arrival of another heat wave.
5. Skip fertilizing. Plants devote all their resources to surviving a heat wave. Because of this, they can’t spare the energy to take up fertilizer, which remains in the soil and can “burn” the plant. After the scorching weather has abated, go ahead and resume your regular fertilizing schedule.