In the food garden
Continue to cut off curly garlic scapes to encourage larger bulbs. You may be able to harvest garlic in late July.
Remove spotted or yellow leaves from your tomatoes. This will slow down early blight and septoria leaf blight. If you suspect late blight, take leaf samples or pictures to your local Extension office.
Protect berries from the birds with bird netting. If some berries look moist or misshapen, check for the maggots of the two-spotted drosophila fruit fly. Destroy all the bad fruit. If a lot of fruit has been set, you can then use rowcover to keep the fruit flies out, but this will also prevent further pollination so wait until they are done flowering. Consult Cornell CE for spray recommendations. Also look out for the marmorated stink bug. The Cornell Insect Diagnostic Lab has good links for both pests at http://idl.entomology.cornell.edu/factsheets/
Keep your food plants weeded, watered, and mulched. Blueberry bushes are particularly sensitive to drought. A five-gallon bucket with holes, next to each bush, provides an easy way to water and measure how much water you’re applying (10 gallons each is good in drought situations, once or twice a week).
Keep tomato branches inside their cages, and guide melon and squash vines.
This is the last month to plant these veggies for a fall crop if you are in zone 5: snap beans, peas, cucumbers, carrots, kohlrabi, summer squash, early sweet corn, green onions. Zone 6 gardeners get a couple more weeks of growing season. Cover newly planted seeds with rowcover to keep them cooler and moist.
It’s time to renew or move the strawberry bed. Moving the plants allows a thorough weed removal, and then there’s still time to plant a succession crop (see above).
Keep the asparagus bed weeded. You shouldn’t be harvesting any longer. Look out for asparagus beetles; drop them in soapy water.
To maximize basil harvest and prevent blooming, cut plants back by one-third, rather than just plucking leaves. You can probably do this three times. You can overwinter a few basil plants in pots on a warm sunny windowsill (put parsley on your cooler windowsill).
Handpick Japanese beetles, Colorado potato beetles, etc. Look for the eggs on undersides of leaves. Use B.t on cabbage family plants. Remember B.t will also kill the caterpillars of desirable butterflies; instead, grow extra parsley, dill, or fennel, to have more black swallowtails. Leave common milkweed in rough areas for monarch caterpillars.
Don’t panic if you have few apples or crabapples this year. We should have a large fruit set next year. Thinning the fruit then may reduce the tendency to biennial bearing that might result.
Black knot is a fungus that affects some plums and cherries. If you haven’t planted plums yet, seriously consider the hybrid plums that appear to be totally resistant. Most of these are products of plant breeding in the upper Midwest, so they are hardy to zones 3 or 4.
It’s finally okay to remove daffodil and tulip foliage – removing it prematurely has a negative effect on flowering. This is also a good time to move the bulbs, or you can dig them up and dry them off, for planting in September.
Early July is a good time to move Colchicums. The dormant foliage should still allow you to find them. Try growing plumbago, Ceratostigma plumbaginoides, as a fall-flowering groundcover with the Colchicum. The foliage will help support the Colchicum flowers and keep them out of the mud.
A good rainy day chore is sorting seed packets. Also, if you forced bulbs this past winter, you can take them out of the pots and store them dry and cool for the summer (except for delicate ones like snowdrops).
Leggy annuals may need to be pruned back to encourage new growth and more flowering. Some annuals don’t take hot weather and may need to be replaced.
Unruly perennials such as spiderwort can be cut back by two-thirds, and then watered. They will send up fresh new foliage. Deadhead some other perennials, like catmint, and salvia either for continued bloom, and improved foliage. For more details, consult the excellent book by Tracy DiSabato-Aust: “The Well-Tended Perennial Garden.”
Bearded irises can be divided and replanted now. Get this done before Labor Day, to allow sufficient time for rerooting. If you want to order more, do so right away. Late-planted bearded irises may heave out of the ground and die in the winter, but if they have enough time to root, they are very winter-hardy. A tip from the Southern Tier Iris Society: put a brick on late-planted rhizomes to prevent heaving.
Continue to go on garden tours at private gardens and arboreta. Take your camera and notebook, because you are sure to get ideas for your own garden.
Mark colors of phlox or daylilies in case you want to propagate them for friends or Plant Sales.
Watch your viburnums for viburnum leaf beetle adults, especially if they were defoliated by the larvae. Consider a pesticide treatment to save the shrubs. Do not cut back branches just because the leaves have been eaten or damaged. Scratch the bark with your fingernail. If it’s green underneath, the branch is alive. Dormant buds under the bark just need time to develop into sprouts and leaves. If the leaf defoliation isn’t too bad, an organic control method is to snip off the twigs that contain the VLB eggs. Although the egg-laying sites are most obvious in the fall, one actually has until April to trim the affected twigs. See the VLB factsheet for details.
This is the last month to fertilize woody plants, without encouraging tender late growth that may not harden off in time for winter. It’s also the last month to prune woody plants—except for dead or diseased wood.
Spring-planted woody plants need to be watered every week unless there is an inch of rain. Ten to 15 gallons per plant is recommended. If you haven’t protected them from deer yet, start planning how to do it.
In the food garden:
This is the last month to plant these veggies if you are in zone 5: broccoli or cauliflower transplants, leaf lettuce, spinach, and turnip. Protect them from the scorching sun with rowcover or milk crates.
The easiest way to expand the veggie garden is to sheet compost now with flattened cardboard boxes. Overlap the edges and then cover them up with whatever you have – grass clippings, woodchips, spoiled hay, or bags of leaves. By spring, most of the weeds will be dead. This is also a good way to prepare the ground for shrub borders, berry plantings, or flowerbeds. You can also use thick newspapers, but they take longer to apply.
Harvest garlic when the leaves are yellowing. Then you can weed the area and plant a late crop (see above). It’s best to rotate where you grow garlic, so pick a new spot with lots of sun and good drainage. Maybe, sheet compost the new spot now, until planting time in mid-October.
Keep up the weeding, watering, and mulching, as needed. Try not to get leaves wet as that might spread disease. Keep a close watch for tomato/potato late blight.
Keep harvesting beans, basil, okra, cucumbers, summer squash, eggplant, etc., in order for plants to keep producing. It’s okay to leave some peppers on the plant to ripen and turn color.
Fall-bearing raspberries should start producing by mid or late August. If you have the variety ‘Heritage’ and have had problems with early fall frosts destroying part of the crop, plant an earlier-bearing variety, such as ‘Polana.’
Enjoy blueberries until Labor Day if you have planted the late-bearing variety ‘Elliott.’ Maybe you’ll have room to add it next spring, if you’ve not planted any!
Nursery stock goes on sale and may be a good money saver if it has been well cared for. Be sure to water weekly after planting if rain is insufficient. Keep the watering up until the ground freezes, unless rain is adequate.
The second half of August is a good time to start to move and/or divide some of the hardier perennials. Try to be done by the end of September.
It’s time to order bulbs for fall planting, to get the best selection of varieties. Lots of spring-blooming bulbs are deer-resistant. Avoid tulips and crocuses, and enjoy carefree alliums, winter aconite, snowdrops, snowflake, Siberian squill, glory-of-the-snow, Puschkinia, Fritillaria, and Anemone blanda. Grape hyacinths send up fall foliage, but even when it’s browsed, it doesn’t seem to affect their vigor.
Repot your houseplants to get them established before they need to be brought back inside.
Keep the lawn mowed at a three-inch height for the strongest root development and drought resistance. But if a drought drags on, allow the lawn to go dormant. It will revive on its own when rains resume.
Late August and early September is the best time to renovate the lawn or to seed a new one.
This is the time to start protecting tree trunks from ‘buck rub’ damage.
— Pat Curran and the Tompkins County Master Gardeners