August Gardening Tasks
During our sultry warm August, there are many activities to do in the garden. In our Southern climate, gardeners have a second chance to replant and add new plants and vegetables to their gardens as we slip into Fall.
Growing fruits and vegetables here is a popular and common activity. Keeping an eye on our treasured edibles is important right now. There is a bounty of tomatoes, sweet corn, green beans and cucumbers to harvest, or go to your local farmers markets to purchase them.
Planting a Fall garden with new trees, shrubs and perennials can also be done starting in late August.
Expand the categories below to learn more about what you need to do this month.
Vegetables
Herbs that can be planted from plants (not seeds!) include bay laurel, Mexican tarragon, and rosemary.
Watch for cucumber beetles and squash vine borer on late summer cucurbits. Carbaryl usually controls these. And monitor tomatoes, peppers, eggplant, squash, watermelons and other susceptible crops for blossom end rot – a calcium uptake disorder. Make sure to lime at planting, if you need lime; otherwise work in a handful of gypsum per 10 square feet of planting space. Don’t use too much nitrogen fertilizer (especially urea or ammonium N). Avoid excess potash and avoid moisture fluctuations. Discard affected fruits.
Think about what you’d like in your fall-winter garden – the options here in Hall County are many! As it gets cooler, you can plant greens, turnips, spinach, lettuce, fall Irish potatoes (early to mid-August), collards, rutabaga, broccoli, bunching onions, leafy celery, carrots, cilantro, cabbage, etc. Call the Hall County Extension office if you need advice on fall plantings. You can plant fall snap beans until about mid-August and cucumbers and squash until late August.
Start seedlings indoors for transplant in September: broccoli, Brussels sprouts, cabbage, kale, collards, onions, lettuce, etc. Most transplants need 5-8 weeks ahead before they’re big enough to be set out.
Clean up around your garden and get rid of dead plants and leaves as many diseases and pests overwinter on infected dead leaves and stems. Late summer or fall is great for applying and mixing needed limestone, so test your soil if needed.
Lawns
Check sharpness of mower blades and repair. Mow turf as needed depending on summer growth. Damaged areas can be the result of insects, disease, or irrigation problems. Be sure to determine the cause so the proper remedy is used. Use a sharp mower blade and only remove 1/3 of grass blade to reduce stress on the lawn.
Watch for problems with brown patch and dollar spot in warm season grasses, especially if you had problems with one of them last year. Don’t overwater now that the rains have backed off and don’t use excess nitrogen fertilizer! Think about putting something out for the grubs this month. Inspect warm season lawns for mole crickets this month and keep a lookout for two-lined spittlebugs in the grass.
Think about winding down summer fertilization of warm season lawns. A high-potash fertilizer in late August can help with winter hardiness if we have a cold winter. But, avoid so-called “winterizer” fertilizers containing high nitrogen.
Continue to treat fire ant mounds, first with bait and then follow with a drench for effective control.
Late summer is a good time to topdress lime if needed (based on a soil test, of course).
This time of year is a good time to aerate cool season fescue lawns (aerate warm season lawns in late spring or summer). Turf-type tall fescue looks best when mowed 2-2.5 inches high. In dry summers and when growing in heavy shade, mowing at 3 inches helps the grass tolerate its environment. In hard clay and baking heat, though, tall fescue will thin out this month and will probably need overseeding this fall. Do not fertilize in summer: brown patch disease is particularly prevalent on lush growth.
Flowers
Remove spent blooms, cut back, and fertilize flowering annuals and perennials to extend the bloom season into the fall months.
If you haven’t already done so, this is the time to begin sowing seeds for fall transplants. Most things need 5-8 weeks to get to transplant size so start early indoors. By starting seeds now, you can have pansies, calendulas, flowering cabbage, and flowering kale, and other cool-season transplants ready to plant in the garden in September or early October.
You can still plant spider lilies (Lycoris) or oxblood lilies (Rhodophiala bifida) now before they start to bloom in September.
Remove spent blooms and seedheads. Cut back, and fertilize flowering annuals and perennials to extend the bloom season into the fall months.
Now is a good time to get your beds ready for pansies, violas, ornamental cabbage and kale, colorful chards, snapdragons, dianthus, ‘Lacinata’ kale and other cool-weather plants. Clean out the beds now or next month and they’ll be ready for planting when cool weather gets here. Dividing of irises is best done now in August and into September, which is the same time of year that new plantings should be made.
Deadhead annuals to encourage late season blossoms. Cut back and fertilize annuals to produce new growth and fall blooms. Take cuttings from geraniums and begonias for wintering indoors.
Trees
Prune and shape hedges as needed. Check mulch layers and add if needed. Prune broken, dead or crossing limbs for healthier plants. Avoid fertilizing ornamentals now and into September so they can harden off before winter.
This is the time to watch for bag worms in pines, junipers, Leyland cypress and arborvitae. They even get on deciduous trees, too. Hand-pick light infestations; Use Bt-kurastaki strain for large infestations. If you see caterpillars on oaks this time of year, they’re probably oakworms. These can strip a small tree in a few days. Spraying small trees and lower branches of large trees with liquid carbaryl will dispense them quickly. And, you’re going to start to see infestations of fall webworm in pecan trees this month. A directed spray of a liquid carbaryl product should help control them, at least as far as you can spray.
Fall webworm (as the name implies) occurs later in the season becoming especially noticeable in August and September. They build large, protective nests (webs) that usually start on the ends of branches, unlike tent caterpillars. Nests increase in size as caterpillars feed. They do not leave the nests until they are ready to pupate. Heavily infested trees can be completely covered with nests up to three feet long enclosing the ends of branches. Fall webworm is a general feeder and will feed on most any tree. It feeds mostly on over 120 different species of deciduous trees including crabapple, ash, oak, elm, maple, hickory, pecan, sweet gum, and black walnut. Fall webworm generally doesn't feed on conifers.
Luckily Bacillus thuringiensis var. kurstaki (Btk) sold as Dipel or Thuricide is effective especially on young caterpillars. With fall webworm and tent caterpillar use high spray pressures to break up the web and get the insecticide inside to the caterpillars and the leaves. If the caterpillars are not there, then insecticide sprays are useless. At that point just good maintenance, including watering during drought periods, is your best tactic. Bt will not affect birds or beneficial insects that may be in the trees to feed on the caterpillars. The insecticide carbaryl (Sevin) can help control the worms in later growth stages. Bt does a fine job on small caterpillars, but if their growth is advanced you may need to spray liquid Sevin on them for good control.
Tearing or pruning the webs and their resident caterpillars out of the tree can also control fall webworms. Obviously be aware of maintaining the shape and health of the tree by not removing large branches. Burning is not advised at all! Although it is aesthetically unpleasing, late season defoliation of deciduous trees as with fall webworm is usually not life threatening for the tree.
If you haven’t pruned spring-blooming shrubs like azaleas, rhododendron, forsythia and redbud, early August is the very latest you can still prune and expect good blooming next year. Spring blooming woody plants will soon start making bloom buds for next spring!
Houseplants
If houseplants are outdoors and are actively growing, you can fertilize foliage plants like ferns at 1 tsp. of a water-soluble fertilizer like 20-20-20 or 24-8-16/gallon of water once every 1-2 weeks. Water to leach out of the container. If the plant is a flowering plant in a pot such as impatiens, coleus or petunias/million bells, use 1 tsp. of a water-soluble fertilizer like 20-20-20 or 24-8-16/gallon of water once every 1 week. Water to leach out of the container. If the plant is a succulent such as jade plant, use ½ tsp/gallon of a high nitrate fertilizer like 20-10-20 once a month.
If houseplants are indoors and in subdued lighting, fertilize once a month with a water-soluble fertilizer (1 tsp./gallon/month).
Water houseplants regularly and fertilize as appropriately to promote growth. Check plants for insects such as scales, aphids, and spider mites. Wash plants to remove dust layers. Make cuttings and repot plants.
Garden Maintenance
Water the garden as needed to prevent drought stress during this warm month. Watering is essential in August. A great way to conserve water is to have a rain barrel.
It is important to clean up, revitalize, and plan for our gardens! This way you can keep your gardens in tiptop shape!
As always, the Hall County Extension office is here to help with your gardening needs. Give us a call or email us.