July Gardening Tasks
Expand the categories below to learn more about what you need to do this month.
Vegetables
Harvest tomatoes at the “mature green” stage (when green tomatoes turn light green) or slightly pink and ripen indoors in the cool of your house. High temperatures inhibit ripening but 70 degree indoor temperatures will bring about rapid ripening.
High July day and night temperatures may cause blooms to abort on regular size tomatoes and green peppers. There is little you can do about this but to wait for cooler temperatures (days: 85-90 degrees F or less). Fortunately though, heat has little effect on cherry-type tomatoes and hot peppers.
It’s still summer, but you need to start planning your fall garden now! Clear out weeds regularly, to prevent competition with your crops for nutrients, space and water. Moreover, they serve as reservoirs for diseases and pests that could get into the garden.
Practice “situational awareness” in the garden and visit and observe your garden at least twice a day, once in the morning and again at dusk. Keep an eye out for pests and beginning diseases on garden plants, as early treatment is always best. Keep an eye out especially for stinkbugs, leaf-footed bugs, hornworms, corn earworm (tomato fruitworm), cucumber beetle, and squash vine borer in the garden. Watch carefully for leaf and stem diseases on tomatoes. Early intervention is critical.
Clear away any diseased and dried out foliage on vegetable plants and on the ground around vegetable plants. When you water, keep water from splashing up on leaves and stems.
Scientists have known for more than a decade that tobacco and tomato hornworms glow blueish or greenish when seen under short-wavelength UV light. Recently, UV flashlights have become widely available and can be purchased for under $15, making night-hunting for hornworms easy and painless. Just look for the glowing critters, pick them off and drop them in soapy water or save them for your backyard chickens! This UV technique will increase your ability to find hornworms considerably!
Consider “trap plants” such as sunflowers or grain sorghum around tomatoes for attracting leaf-footed bugs away from your tomatoes.
Where possible, try to use low-impact pest and disease controls on your garden. Use spinosad or pyrethrum for chewing insects like grasshoppers and flea beetles. Use insecticidal soap for aphids, thrips and whiteflies. Diatomaceous earth is useful for slug control and for aphids and thrips. Neem oil is useful as both an insecticide and fungicide (powdery mildew). Old fallbacks for garden pest control include things like carbaryl or fungi such as chlorothalonil or a copper fungicide.
Check your tomatoes and other susceptible crops for blossom end rot on the fruit as it begins to form. This is usually an indication of a calcium deficiency. Place and work in a handful of gypsum (land plaster) in the soil beside the tomato at planting (or later) to help prevent this. Foliar sprays such as blossom end rot spray may help alleviate the problem in tomatoes. Nothing will "heal" the fruit with rot on it, so remove and discard them. You can minimize blossom end rot issues in tomatoes, peppers and squash by maintaining a good soil pH (6-6.5), keeping the soil evenly moist (use mulches), avoiding fertilizers with high urea or ammoniacal nitrogen, and maintaining good soil fertility.
Some planting times for more common vegetables for this time:
Pole beans, lima beans - Jul. 1 – August 1
Cucumbers - Jul. 15 - August 15
Bell Peppers - Jul. 15 – August 10
Summer squash - Jul. 25 – August 25
Tomatoes – June 15 – July 15
If you’re going to raise seedling transplants of cool season cole crops such as cabbage and collards, start indoors now in the cool of the house and allow about 6-8 weeks before planting in the fall.
Planting time for cole crops:
Broccoli, brussels sprouts, kale, collards – plant in the garden between August 1-September 1 from transplants.
Cauliflower – August 1-August 15 from transplants.
Cabbage – August 1-October 1 from transplants.
Solarize the vegetable garden patch using solar heat that you plan to use for fall planting. It takes four to six weeks to kill weeds, disease and nematodes, so start now. Call the Hall County Master Gardeners for details on how to do this!
Fruits
Continue to inspect fruit trees for fireblight. If you had problems with fireblight last year, you will need to spray your blooms this year to prevent the spread. The best defense is a fireblight-resistant variety. There is no effective treatment for this disease although some have found copper-based chemicals useful is suppressing it to some degree.
If you haven’t done this yet, thin out the fruits on your fruit trees to produce good sized crops. This also helps to minimize brown rot. Protect any developing fruits from birds and squirrels by placing netting around your plants.
Peg down runners on healthy strawberry plants to create more plants for fall planting. If you don't need more plants simply remove the strawberry runners completely.
Lawns – Let grass clippings fall to return nutrients to soil and grass. Keep mower blades sharpened. Replace lawn mower air filter and change lawn mower oil per owner's manual.
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 blades to reduce stress on the lawn. A good general “rule of thumb” for mowing any grass is to mow when you need to remove a third of its height to bring it down to the recommended height.
Turf-type tall fescue looks best now 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.
Warm weather encourages rapid unsightly weed growth like nutsedges and patches of crabgrass or dallisgrass – topically apply specific labeled lawn weed killers can be used. Just be careful not to get the chemicals on your turfgrasses.
Continue watching 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 or overfertilize with nitrogen!
Watch for chinch bugs in St. Augustine lawns if you have this tender, warm-season grass (it’s not really the best choice for Hall County!). Be thinking about white grub treatment in your lawn – here this will be done generally in August and early September. Also, inspect warm season lawns for mole crickets this month. Eliminating these insects requires diligent work in June, July, and early August.
Don’t forget to apply nitrogen to Bermuda, zoysia and St. Augustine lawns this month. You can also apply iron to centipede lawns to encourage green color without excessive growth.
If you’re going to seed warm season grasses, this is the last good month to do it (the best time to plant is in the spring and summer. Fall-seeded warm season Bermuda seed can be planted but is not encouraged – use unhulled Bermuda for Bermuda turf established in the fall. Wait until fall to plant tall fescue and be careful what you put out – red fescue and other fine fescues don’t do well here in the summer!
If you have not yet broadcast fire ant baits apply your first treatment any time this month. Be sure to apply fresh bait, and do it at the correct time of day (fire ants only forage actively when the ground temperature is between 70 and 95 degrees F). An effective treatment is to follow in a week or so with a liquid drench. It’s good to alternate between at least several chemicals for good fire ant control to prevent development of insecticide-resistant fire ant populations.
Remember that any time your warm season lawn is actively growing is a good time to aerate.
Flowers
Coleus, ornamental pepper, and tropical milkweed planted now should last until November. As the heat continues, keep annuals evenly moist. You can plant spider lilies (Lycoris) now before they start to bloom in September or later. Now is a good time to plant Italian arum as well.
Japanese beetles will defoliate plants in short order. Keep a sharp lookout for them. If you find an infestation use a spraying of liquid carbaryl (Sevin, etc.). Observe all label precautions on mixing and use. Do not use dusts due to the problem with application - a spray made using the liquid form of the product will work fine.
Cut back faded plants to keep beds tidy. Deadhead annual and perennial flowers as needed to keep them blooming and to keep them from making seed (unless you want to collect the seeds). Watch for “Clematis Wilt” especially on Jackmann clematis and evergreen Clematis armandii: look for wilting black leaves and stems. Cut out all affected material and discard (but not in the compost pile).
Cut back growth in hanging baskets (but not ferns) to encourage renewed flowers and/or foliage. Feed your baskets well after doing this. Water all containers and baskets thoroughly and regularly in hot weather. Feed them with a balanced water-soluble fertilizer once every week or up to every 2 to 4 weeks depending on the plant.
In late July and into August, take cuttings from tender plants like brugmansias for over-wintering indoors. You can still take cuttings from most shrubs and many herbaceous perennials.
Make sure you turn the contents of your compost bin regularly to keep it well aerated. If you see grubs or soldier fly maggots in the compost, this is quite natural. You can sieve these out if necessary.
If you need to prune azaleas, any cutting should be made by mid-month to protect developing buds for next spring’s blooms.
You can purchase ornamental cabbage and kale transplants this fall or you can grow your own by starting seedlings indoors under lights at this time. Allow 6-8 weeks ahead of planned planting to flower beds.
Trees
Water newly planted shrubs and young trees (planted within the last three to five years) during dry weather. Keep plants mulched to conserve moisture and cool the roots. Remove sucker growth from the base of trees and along branches. If sucker growth is extensive, examine plants for signs of stress. Prune diseased, dead, or hazardous limbs.
Remember that bag worms can kill a tree if it is heavily infested. Inspect your trees periodically - bagworms seem to like juniper, arborvitae, and pines, but they are will attack many broadleaf shrubs and trees such as rose, sycamore, maple, elm, and black locust. Hand-picking light infestations works well; applying the bacteria Bacillus thuringiensis kurastaki strain will also take care of the problem.
Caterpillars may still be present on trees and shrubs. Large trees can normally withstand caterpillar feeding but specimen shrubs and small trees may need treatment if damage is extensive.
Now is another good time to prune most trees and shrubs. July and August are good months to prune azalea, dogwood, forsythia, redbud and rhododendron. They should be pruned after they bloom, but before bloom set in the fall. Oakleaf hydrangea and late-flowering azalea cultivars might also be pruned now. Avoid any pruning in the spring and fall if at all possible.
Irrigation
Irrigate in the mornings to give water on the leaves of plants and turf time to dry before evening. One inch per week is the appropriate amount for most lawns and vegetables (except sweet corn and yellow squash, which may require up
to 1.5 to two inches/week depending on growth stage). Include rainfall in this amount. And make sure that you adjust your water applications with plant growth stage and time of year - one size definitely does not fit all for the entire year. Do not irrigate every day! There are a few exceptions to this rule (such as potted plants), but only a few.
Make certain bird baths are topped up in hot weather but clean out often to keep mosquito larvae from getting a foothold.
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).