Guest column: August gardening tips for Oklahoma

The Daily Ardmoreite
Pat Neasbitt
Master Gardener

It has been a pretty nice first week of August weatherwise with cooler temperatures and a little rain. Unfortunately, the rest of the month may live up to the “dog days of summer” heat and humidity that make gardeners long for fall. The following are things that can be done this month in addition to the never-ending tasks of watering, deadheading, and controlling weeds.


· August is a good month to start your fall vegetable garden. Bush beans, cucumbers, and summer squash can be replanted for another crop. Beets, broccoli, carrots, potatoes, lettuce, and other cool-season crops can also be planted at this time. For further information, check out OSU Factsheet HLA-6009.

· Soak vegetable seeds overnight before planting. Once planted, cover them with compost to avoid soil crusting and keep moist constantly. Mulch after germination to keep planting bed moist and provide shade during initial establishment.


· Towards the end of the month, divide and replant spring-blooming perennials like iris, peonies, and daylilies, if needed. Discard older portions, and replant the keepers in soil improved with compost.


· Water compost during extremely dry periods so that it remains active. Turn the pile to generate heat throughout for proper sterilization.

· Always follow directions on both synthetic and natural pesticide products, if you choose to use them. More is NOT better.

· Watch for high populations of caterpillars, aphids, spider mites, thrips, scales, and other insects on plants in the garden and landscape and treat with IPM (Integrated Pest Management) by handpicking, spraying with a hose, or spraying with Insecticidal Soap.

· Water all plants thoroughly unless rainfall has been adequate. It is better to water deeper, less often, and early in the morning. Roots of shrubs and perennials are usually 12" deep and tree roots are about 18"- 24" deep so just sprinkling the top of the soil is a waste of time and water and causes harm to plants.

Trees and Shrubs

· Discontinue deadheading roses by mid-August to help initiate winter hardiness. New growth forced by pruning is susceptible to insect and freeze damage.

· Don't fertilize shrubs and trees until next spring. The new growth will also be susceptible to insect and freeze damage.

· Watch for the second generation of fall webworms in late August to early September. Remove webs that enclose branches and destroy them. If they are too high to reach, you can use a long pole to poke holes and pull them down. Don’t stand under the web when you pull it down! I let the birds take care of the webworms when they fall to the ground.

Lawn and Turf

· Grassy winter weeds like Poa annua, better known as annual bluegrass, smooth brome, henbit (the one that makes your lawn a pretty purple carpet), mouse-ear chickweed, common chickweed, cranesbill, and shepherd’s purse are the most common winter annual weeds that plague Oklahoma gardeners during the cooler months. These winter weeds are not only unsightly, but heavy infestations can be damaging to Bermuda Grass during spring green-up.

· A good rule of thumb for pre-emergents to keep winter weeds from germinating is that they need to be applied from the third week of August through September 15th in Oklahoma. After September 15th, weed seeds are already starting to germinate and will show up as big ugly green spots in your dormant lawn in the winter. We in southern Oklahoma can push the date to apply pre-emergents through October, usually. I know we were still mowing through October the last two years, and it was hot until Thanksgiving; so the soil temperatures were still high enough that winter weeds had not begun to germinate. Check Oklahoma Mesonet for in-depth coverage of all things related to Oklahoma weather, including soil temps at different depths.

· For more information on lawn care in Oklahoma check out the following OSU Factsheets:

HLA-6420 Lawn Management in Oklahoma

HLA-6421 Controlling Weeds in Home Lawns

L-253 Don’t Bag It Lawn Care Plan

If you are interested in learning more about lawn care and fall gardening in southern Oklahoma plus much more, Betty Sue Tow and I will be teaching Home Gardening & Landscaping for the fall semester on Mondays from 6-8 at Southern Tech in Ardmore. 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!