Here is some timely information regarding July and August gardening from the now-retired James Quinn, horticulture specialist.
Supplementing tomatoes with nitrogen as the summer progresses is important for keeping strong vigorous growth and dark green foliage, two traits making tomatoes leaves more resistant to foliar diseases. It will also help the plant to continue producing fruit, avoiding the August 'swoon', which can often happen following stressful weather and a heavy fruit load. Fertilization should be made 1-2 weeks before first fruit ripening, two weeks after first fruit picking, and a month later. Many home gardeners won't supplement more than once; use of a time release fertilizer or a natural product like compost at first fruit picking is a good compromise.
The abundant growth of herbs in summer can provide a number of opportunities and few challenges, with flowering being the unifying growth phase. Many gardeners know the flavor of the herb is considered best just before it flowers. So when possible, try to use the leaves when the flower buds are developing. Basil can be continually pinched or cut back and kept mostly vegetative all season long. But some herbs like oregano and thyme will likely flower no matter how diligent you are. Enjoy the bees and butterflies that they attract. While most herbs seem to only suffer minor insect damage, I have been intrigued to see parsley, dill, fennel, and other umbel-forming plants such as carrots munched back by caterpillars. Their common name is aptly "parsleyworm" and the adult is the black swallowtail butterfly, a pretty thing worth tolerating around the garden.
Garlic may be interpreted as a spice/herb or a vegetable. Hardneck garlic varieties will produce an edible flower stalk, or a "scape," generally in early July. They should be picked off, as the energy will be directed to the bulb, and these tender "scapes" are considered a delicacy, cooked and eaten similar to asparagus.
Missouri often experiences a hot/dry spell in July and August. Letting a lawn go dormant (the above-ground portion of grasses will turn entirely brown and senesce) and taking a break from mowing can be beneficial but not without risks. Even though grasses are dormant, watering restrictions or failure to minimally irrigate may result in extended dry periods can cause large ground cracks, severe soil drying, and excessive loss of turf cover, even when watering is resumed later in the summer or early fall. Summer dormancy of grasses is a mechanism that helps a lawn to survive, but it does not guarantee that a lawn will fully recover from the browned-out stage.
Dormant lawns should receive at least 1 inch of water every two or three weeks during summer to prevent complete turf loss. Grasses may not show a noticeable greening, but that amount of irrigation should be sufficient to hydrate the lower plant portions and increase the recovery once adequate moisture is available.
Our late spring will push berries like blueberries, blackberries and mulberries to ripen in July. Fall raspberries will ripen in August, toward the end if the summer isn't too hot. The big unknown for berries again this year is the dreaded Spotted Wing Drosophila. The pest is closely related to the common fruit fly, but with a knife. The barrier to a common fruit fly is it has to wait for a crack, fissure or other entry point to open in fruit, then it can lay its eggs. And everyone knows how quickly they reproduce.
Spotted Wing Drosophila doesn't have to wait for the entry point. Once the fruit nears ripeness, then its egg-laying ovipositor can go through the skin to insert eggs. Can it get worse? Yes! You don't see any cuts, but open up the fruit, and there they are! Dozens of tiny squirming worms (maggots technically — these are flies, after all). Only a few overwinter and as the season progresses, the population builds. Blackberries and fall raspberries are the most susceptible fruits.
Apples, peaches, paw paws and figs will all start to ripen during these months. Last year, I was surprised by an unexpected wildlife pest: possums! I first noticed green persimmons under my tree in July, and suspected squirrels. Over about 6 weeks, I trapped and relocated four possums and one raccoon. I was further surprised to notice that other fruit I had blamed on squirrels (figs, peaches, apples) "hung around" better. I came to learn, from Missourians more experienced than myself, that possums are known for their interest in persimmons.
Peter Sutter is a lifelong gardening enthusiast and a participant in the University of Missouri Extension's Callaway County Master Gardener Program. Gardening questions can be sent to [email protected]