July in Zone 3, which hugs the border between the U.S. and Canada in North America, is characterized by a sense of urgency. With a growing season of just two to four months, only plants that can withstand “chilling” even in midsummer are likely to survive. Spinach is one of the best crops for this climate, as are carrots, scallions and Swiss chard. All can handle soil temperatures in the 50°F range and still grow. All can be planted this month for a bountiful fall harvest. Despite the cold winters, summers can be hot. And while some areas are quite dry, others average as much as 37 inches of rain a year.
Raised beds allow the northern gardener to make the most of the growing season. The soil warms faster in a raised bed, it is easier to use floating row covers or to construct a cold frame around a raised bed, and it is easier to amend soil in a limited area, maximizing the space and time in which the garden has to grow. Consider adding one to your garden space this month and planting it with fall vegetables. Use it again next spring to get summer vegetables or flowers in the ground a bit sooner.
- Stop fertilizing perennials by mid month. You don’t want to encourage new growth that will be damaged when frost comes.
- Divide iris that are crowded, did not bloom well or just need moving. Cut them apart and discard old or damaged rhizomes. When dividing iris, wash the old soil from the roots and let then soak over night to plump them up. Pot up freshly cleaned rhizomes to share or plant them back into a prepared bed.
- Clip off the dead flowers from your coreopsis, garden phlox, dianthus, feverfew, daisies, yarrow, and cornflowers. Cleared of spent blossoms, some perennials will reward you with another wave of blossoms.
- Reduce height on tall perennials by cutting plants back by one-third around July 4. Candidates for this treatment include goldenrod, aster, and joe-pye weed.
- Keep deadheading to keep the garden neat and flowers blooming.
- Cut back annuals like petunias in midsummer to encourage fresh growth and flowering. Reduce plant height or length by one-third or more.
- Cut flowers for indoor bouquets. They’ll keep best if picked in early morning.
- Fertilize strawberry plants with 21-0-0 or another source of nitrogen, like cotton seed meal, when the harvest is finished.
- Harvest early cabbage varieties while the heads are still tight.
- Side-dress long-season crops with 5-10-5 or other balanced fertilizer. (Side dressing means digging a shallow trench either beside or around a plant six or so inches out from the stem. Sprinkle in fertilizer, compost or other amendments, cover with soil and water deeply to get the nutrients down to the roots.)
- Harvest herbs with sharp scissors in the early morning. Cut them often to promote more growth, and do it before they flower. Many herbs are at the height of their flavor just before they flower. None of them are served by allowing them to flower.
- Plant beets, escarole, kale, collards, lettuce, radish, turnip, chard, and spinach for a fall harvest.
- Watch for sugar-like droppings on tomato plants. These are a sign of psyllids – tiny, flat, oval insects – on the undersides of the leaves. Top leaves may be curled and yellowed and leaf veins may be purplish. As soon as possible, spray with insecticidal soap or dust with sulfur.
- Thoroughly spray aphid– or spider mite-infested plants with insecticidal soap or a strong water spray. Repeat as needed.
- Hand-pick and destroy Mexican bean beetles. Squash the spiny, yellow larvae found under skeletonized bean leaves.
- The first crops of beets, spinach, and cucumbers are likely harvest-ready or nearly so. After you pick, sow new seeds for a flush of fresh produce in five, six or seven weeks. Same with green, yellow, and pole beans as they mature. This is called succession planting.
- Peas fresh from the garden are a delectable treat. For the sweetest harvest, pick regularly, which will also help increase the production from your vines. Pods at the bottom of the vines mature first. English or shelling peas should be picked when the pods are bright green and feel smooth. The peas inside the pods are full sized, but not hard. Pick snow peas when the pods are still flexible and full sized but the peas inside them haven’t begun to swell. Edible-podded snap peas are best when the pods are round and full. If you miss peak picking time for some pods, harvest them anyway and add them to the compost pile to keep vines producing new pods.
- Sow more bush beans. Keep making small succession plantings of bush beans to have a continued harvest throughout the summer. Sow seeds every 10 days up until about two months before your expected fall frost date. Later plantings are less likely to be troubled by Mexican bean beetles.
- Dust or spray Bt (Bacillus thuringiensis) if hornworms on tomatoes or cabbageworms on broccoli, cabbage, and cauliflower are causing a lot of damage.
- If you have an established strawberry bed, it’s time choose the plants that will bear next year’s crop. Look for the strongest, largest plants and cultivate these. Remove other plants and their runners. Water and fertilize these plants the rest of this growing season to ensure a heavy crop next year.
- After picking summer-bearing raspberries and blackberries — including wild berry patches you may tend — cut fruiting canes to the ground but leave the ones that did not bear fruit this year. Add compost around the base of remaining canes to promote strong growth. These canes will bear next year’s fruit. Tie to supports as needed.
- Check the soil moisture level around recently planted trees and shrubs. Water them thoroughly if the soil is dry. Keep the soil moist during the entire first growing season to establish deep roots. In case of drought, remember to water your largest and most expensive plants first. Those are your greatest investment and would be the most difficult to replace.
- Keep about four inches of mulch around the planting area to hold the moisture. Keep mulch pulled about 6 inches away from the main stem or trunk.
- Check the top and outer leaves of trees and shrubs for drought injury: brown or tan scorch on broad leaves and brown needles or dead tips on conifers. If damage is present, circle the tree a few feet from the trunk with a drip hose and water for an hour or more every few days until you see new growth start to appear without damage.
- If you sprayed fruit trees for coddling moths once in the spring, it’s time to spray again now.
- Survey American elms for wilting and yellowing leaves and branches, initial symptoms of Dutch elm disease. If these symptoms are present, immediate action is required. Talk to an arborist about what to do.
- Japanese maples need some protection from the heat, wind and scorching sun in summer. Shade cloth or misting on hot days helps. Consider relocating these tender trees if they are in an exposed location.
- Check your spruce trees for the pineapple-shaped galls formed by spruce gall adelgids (also sometimes called spruce gall aphids). Feeding by these pests causes distorted growth, yellowing needles, and weak growth that can break in storms. Norway spruce is especially susceptible, but white, black, and red spruce may also be infested. Look for the 1/2 to 1 inch long, greenish-purple galls at the base of the new growth. Prune out and destroy them now, before they open and turn brown later in the summer and the adelgids feeding inside emerge to lay eggs.
- Water the lawn 1 to 1 1/2 inches per week through this month if the weather is hot and dry.
- Continue mowing, as needed, to keep the height 2 -1/2 to 3 inches. Longer grass suffers less in drought and heat than shorter grass.
- Save maintenance and water by allowing perennial rye and Kentucky blue grass lawns to go dormant during the summer
- Wait to fertilize until late August or September when temps cool and grass grows actively again.
- Dig up weeds now, but don’t spray the lawn with herbicide until fall.