Gardening in extreme heat is no fun, but no matter how hot it gets, you still need to water, weed, and deadhead. When the temperatures hit the 100’s in the summer months, and usually the first part of September, it is best to minimize time outdoors during the hottest parts of the day, for the sake of the gardener as well as the garden.
- Follow the shade. It feels at least ten degrees cooler in the shade, and there is more of a breeze. Work in the yard early in the morning and late in the evening. Drink plenty of water, wear a hat, and use sunscreen and mosquito deterrent, since those also are prime times for them to be out. Sitting in the shade pulling weeds or deadheading can be very relaxing at times – a great stress reliever, too. It's good exercise and free therapy.
- Mulch the soil. Having a layer of mulch three or four inches deep keeps moisture in the ground which means less watering. Mulch cools the soil; keeps weeds down that will steal nutrients and water from plants; and breaks down to improve the soil structure, feed the soil and the plants. Mulch would be worth it even if the only benefit were less weeds to pull in the summer; however, it does so much more.
- Stop fertilizing. Extreme heat brings on a form of dormancy in plants, and growth slows down as a form of self-preservation. Fertilizing speeds up growth rate, and it’s just too hard on plants when it’s really hot. The exception to this rule is container plants because nutrients are flushed out each time they are watered. For container plants, apply compost tea, fish emulsion, or liquid seaweed about every two weeks. A time-release fertilizer also is a life safer for annuals in containers that bloom their little hearts out all summer. Don’t forget to deadhead religiously to keep them blooming.
- Water early. As always, water early in the morning to minimize fungal diseases. Put water at the roots and try not to get the leaves wet. This also saves water because it evaporates quickly when it is hot and windy. Ideally, one should provide about an inch of water to plants a couple of times a week in the summer. If crepe myrtles, lantana, and purple coneflowers look wilted, it is definitely time to water. Use drip irrigation hoses, set the in-ground sprinkler timer for 5:00 in the morning, and water deeply but less often. Make sure sprinkler heads are adjusted to put out a coarse spray instead of a fine mist that will evaporate or blow away before reaching the soil. Quit watering the lawn. Yes, the Bermuda grass will go dormant; however, it will green up again with the first rain.
- Stop pruning. Pruning, like fertilizing, increases new growth at a time when plants would just as soon barely grow at all. Minimize summertime pruning to only removing dead branches or deadheading spent flowers. Stop deadheading roses now so they can build up resistance to winter cold and avoid damage. Any time you prune, new growth occurs that is lush and tender and will likely be killed by heat, the first frost, or eaten by hungry insects. It is best to wait until mid to late February to prune so plants can harden off naturally this fall to better survive winter.
- Divide spring-flowering perennials. It is time to divide spring-flowering perennials such as irises, Shasta daisies, oxeye plants, gaillardias, cannas, daylilies, violets, liriopes, and ajugas. Of course, anything you divide, and replant now will require extra care to survive the heat and drought. Put compost in new planting holes and water daily until plants are growing on their own. It takes about 6 weeks for roots of new plants to become established. You will know when they are past the crucial stages that require your constant care when you see new leaves starting to grow. By then it will hopefully be cooler, and rain will be more abundant.
- Cut back on mowing. Turf grasses slow their growth rates in response to heat waves which means you shouldn’t have to mow as often. That's a good thing when it's so hot it feels like a sauna as you step outside. When you do mow, raise the blades on the mower and cut the grass high, at least 2 inches for Bermuda. The taller the grass, the deeper the roots. The thicker the grass, the better it crowds out weeds. Either mow early in the morning as soon as the dew has dried, or late in the evening to give the grass time to recover overnight. Mowing during the heat of the day puts a lot of stress on the grass, not to mention the one doing the mowing.
- Test your soil. This is a good time to get your soil tested. Usually, the services are available through the local Extension Office for a nominal fee. Take samples 6 to 8 inches deep in various places. Mix well in a clean bucket and put up to one pint of dry soil in a clean bag. Label with your name, address, and what you plan to grow in the area being sampled. Stay safe, stay cool, and happy gardening!