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 in Oklahoma hit the 100’s in August and, usually, the first part of September, it’s 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. I’ve found 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. Wear a hat and sunscreen. Drink plenty of water. I actually find sitting in the shade pulling weeds or deadheading 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, cools the soil, keeps weeds down that will steal nutrients and water from plants, and will break down to improve the soil structure and feed the soil and the plants.
• 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 the 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, you can apply compost tea, fish emulsion, or liquid seaweed about every two weeks. Annuals in containers respond well also to liquid fertilizers every week to 10 days such as Proven Winners or MiracleGro water-soluble fertilizers. You can reapply a time-release fertilizer now that will last until cool weather. Osmocote or a similar brand works especially well for plants in containers because it is activated with warm soil temperatures.
• 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, you should provide about an inch of water to your plants each time you water. If your crepe myrtles, lantana, and purple coneflowers look wilted, it is definitely time to water. Use drip irrigation hoses, set your 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; but 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 removing dead branches and 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 the first frost or eaten by hungry insects, and grasshoppers are in abundance right now. It is best to wait until mid to late February to prune so plants can harden off naturally this fall to better survive winter.
• Stop planting. The survival rate of new plantings drops dramatically when the temperatures rise. That’s true even of drought-tolerant plants. Until the roots are established, they just can’t take up water quickly enough to keep up with what is lost through transpiration when it’s really hot. If you are forced to rescue plants from Lowe’s clearance rack or Wal Mart parking lot, you can probably maybe save them by cutting the top growth back by about one fourth, planting in good garden soil, mulching with 3-4 inches of hardwood mulch – NOT fake dyed red or black stuff – and watering daily until new growth starts, letting you know that the roots are becoming established.
• Cut back on mowing. Turfgrasses slow their growth rates in response to heatwaves which means you shouldn’t have to mow as often. That’s a good thing in August when it’s so hot it feels like a sauna when you step outside. When you do mow, raise the blades on the mower and cut the grass high. 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.
• This is a good time to get your soil tested, and the OSU Extension Office or Noble Foundation provides soil testing for a nominal fee. Take samples 6”-8” deep in various places. Mix well in a clean bucket, and put up to a pint of dry soil in a clean bag. Label with your name, address, and what you plan to grow in the area being sampled – lawn, vegetables, ornamentals, etc.
If you want to learn about gardening in our unique (crazy) southern Oklahoma weather but were afraid to ask, Betty Sue Tow & I will be teaching Home Gardening & Landscaping at Southern Tech for the fall semester from 6-8 p.m. Mondays You can go by to enroll or call 580 223-2070.
Learn what, when, where, and how to plant in Southern Oklahoma, and how to work with what you have to make a lovely yard that is both beautiful and beneficial for the environment. Classes will include Organic Gardening, Landscape Planning, Xeriscape Gardening, Native Plants, Vegetable Gardening, Oklahoma Proven Plants, Lasagna Gardening, Raised Beds, Crepe Myrtles, IPM, Pass Along Plants, Cottage Gardening (New American Gardening), Soil Preparation, Seed Starting, Plant Propagation, and lots more. Hope to see you in class & Happy Gardening!