1. Planting and Transplanting
Planting and transplanting should be avoided in hot weather, as it creates a lot of stress and often causes plants to wilt or even die back entirely. Many seeds also won’t sprout when temperatures get too hot, so it’s best to wait until temperatures drop to resume planting.
Late summer is often the best time to plant veggie seeds for fall harvests, while many perennials can be transplanted in fall, up to 4 to 6 weeks before the first frost is expected in your area.
2. Applying Fertilizer
During hot spells, plants devote most of their energy to conserving water, and they just don’t absorb fertilizer effectively when temperatures exceed 90°F. Continuing to fertilize plants when they’re drought- or heat-stressed leads to fertilizer waste and increases the risk that fertilizer will burn your plant's roots and stems.
3. Pruning Heavily
If your plants have broken, damaged, or diseased stems, it's OK to prune them away even during heat waves. But it’s best to avoid any unnecessary pruning as temperatures climb. Pruning leaves plants more vulnerable to drying out and reduces their energy reserves, which plants need to survive spells of hot, dry weather.
4. Watering Too Little
Plants of all sorts need more water during hot weather. It's particularly important to water potted plants and any newly planted trees, shrubs, and perennials regularly over the summer. Plants in containers dry out much faster than plants in in-ground gardens and may need to be watered multiple times a day during heat waves. Although native plants are famous for needing less water than non-natives, even these tough plants may need a bit of extra water during extreme heat.
Installing shade cloth over vulnerable plants helps reduce issues like leaf scorch and keeps plant pots from drying out quickly when temperatures soar.
5. Watering Too Much
During hot weather, it is tempting to overwater plants, which leads to soggy soil and, in severe cases, root rot. Although the amount of water specific plants need varies, most vegetables, herbs, and flowers should be watered when the top 1 to 2 inches of soil feel dry. If garden soil still feels damp to the touch, it’s best to hold off on watering even if there’s hot weather on the forecast.
Container garden on a patio with outdoor furniture
6. Watering at the Wrong Time
Plants absorb water best in the early morning or the early evening when temperatures are cooler. However, if you water plants during mid-day when the sun is at its peak, you’ll lose a lot of moisture to evaporation and potentially increase the risk of issues like leaf spot. For best results, water plants slowly and deeply and direct your hose at the soil line so plant leaves stay dry and are less likely to develop powdery mildew and other problems.
7. Forgetting to Mulch
Mulching, unlike watering, may be perceived as optional, but it is one of the best ways to conserve soil moisture and keep weeds from intruding. It’s generally best to spread mulch either in spring or fall when cool weather makes it easier to work outside, but if you haven’t mulched yet and you know a hot spell is coming, you may want to apply a quick layer of mulch at least over the soil of potted plants.
8. Mowing Grass Too Short
Just like plants in the garden, turf grass dries out faster in summer, and mowing lawns too short increases the risk of heat and water stress. As temperatures rise in summer, it's recommended to let lawns grow a little longer and to trim cool-season grasses when they’re 3 to 4 inches long and warm-season grasses when they grow to 2 to 2 ½ inches in height. Letting grass blades grow in this manner helps to shade the soil and can naturally reduce the amount of water your lawn needs in summer.
9. Ignoring Weeds
While many garden plants grow more slowly in hot weather, some weeds are undaunted by heat and use hot spells to gain a foothold in gardens. Even in summer, it’s important to weed regularly to ensure weeds don’t take over and compete with your garden plants for moisture and space. Make weeding easier on yourself by weeding when the weather is cooler in the morning or the evening and applying mulch over empty soil where weeds may creep in.
10. Not Harvesting
Pests are often more active during the peak of summer heat, and waiting until temperatures cool to harvest crops like tomatoes increases the risk that your produce will be damaged by pests before you harvest. On top of that, supporting developing fruit requires a lot of energy and moisture from plants, and leaving ripe fruit on plants too long can make plants more stressed and vulnerable to drying out.
As with weeding, try to harvest during the morning or evening to avoid the worst of the heat, and don’t forget to hydrate often while you work out in your summer garden.
