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As the weather turns and harvests shift from plump fruit to cool weather greens, our minds turn to slower subtler rhythms of late summer and early fall gardening. No matter where you are in the west, we’ve got tips and strategies for making the most of your backyard.

Kathleen Brenzel, Johanna Silver, and Mike Irvine  – September 10, 2020 | Updated September 11, 2020

All Regions 

Harvest

For lasting bouquets, snip flowers early in the morning. Use sharp pruners and immediately place each stem into a bucket of cold water set in the shade. 

Maintain 

When you mow, let clippings drop to the ground. They contain enough nitrogen to reduce the amount of lawn food you need to apply every year. 

Layer chopped green matter (like spent flowers and vegetable waste) with brown matter (like dairy manure or straw) in a 4-foot mound. Water weekly and turn the pile every two weeks for finished compost in time for fall planting. 

Check drip-irrigation lines for leaks. Because they discharge water slowly, it’s easy to miss problems until plants start dying. 

Pull weeds by hand or spray with undiluted white household vinegar. White vinegar will kill most weeds, including thistle; large established weeds may require multiple applications. 

If you have a bagging mower, run it over garden waste before you dump it into the compost pile. Chopping can double the speed of compost formation, especially if you water the pile at least weekly and turn it every two weeks. 

If honeybees and other pollinators are scarce in your garden, hand-pollinate plants by using a fine-tipped paintbrush to dab pollen from one flower and deposit it in an adjacent one. 

Test sprinkler output by putting an empty tuna can in the middle of the pattern. See how long it takes for the can to collect an inch of water (most lawns need that amount every week) and adjust accordingly. 

Protect

If you’ve worn a trail through your lawn or flower bed, turn it into a real path. Dig out the top 6 inches of soil; fill with 4 inches of crushed rock; water and roll or tamp it firm; then top with 2 inches of crushed quarter-minus gravel. 

Reduce the risk of fire danger by clearing debris from your yard, pruning any tree limbs closer than 15 feet from the roof, and maintaining a buffer of low-growing, irrigated plants around your home. 

Tomato Cage

Thomas J. Story

Northern California 

Plant

Grow seedlings of herbs such as chervil, dill, and watercress in well-draining soil in a location that receives four to six hours of sunshine. Once plants are established, snip leaves to add to salads. 

Sow seeds for cool-season root crops such as beets, radishes, rutabagas, and turnips in an area with full sun and well-amended soil. 

Creamy white Nicotiana alata releases its scent after dark, an alluring prospect on warm summer evenings. ‘Grandiflora’ (which has trumpet-shaped flowers on plants that can reach 3 feet) has a strong scent, as do hybrids in the Perfume series. Plant as an annual, although in mild-winter areas, it may over-winter. It will also reseed.

Harvest 

Cut artichokes when flower buds (the part you eat) reach full size but before bracts begin to spread open. Leave 11⁄2 inches of stem—it has a flavor similar to the artichoke heart once cooked.

Garlic is ready when the tops yellow and fall over. Use a spade or digging fork to loosen and lift bulbs out of the soil; store them in a well-ventilated, shady location for 2 to 4 weeks, ideally hanging upside down. 

Maintain 

Deep-water mature trees to help them through drought. Stick a shovel in the ground in five to seven locations beneath the tree’s drip line to loosen the soil. Fill each hole with water slowly, allowing the moisture to penetrate the soil. Repeat as needed. 

Pull back on watering tomato plants to prevent cracking. Remember that with tomatoes, you’re growing fruit, not foliage; it’s okay if the leaves start to look ragged. 

Treat iron deficiencies in avocado, citrus, and other fruiting trees. Yellowed leaves with green veins is called chlorosis; applying fertilizer containing iron chelate according to label instructions can help correct the problem. Trees planted in heavy clay soil are especially susceptible to deficiencies. 

Protect 

Check tomatoes for leaves that are yellowing or wilting after watering—both are signs of fusarium wilt. Toss infected plants into the green-waste bin. To avoid the soil-borne fungus next year, select disease-resistant varieties, marked with an F on their plant tag, and don’t grow tomatoes in the same spot. 

Move houseplants away from windows if their leaves seem to be burning in the strong summer sun. Be sure to keep plants watered in air-conditioning; dry air is hard on them. 

Northwest 

Plant 

Order spring-flowering bulbs this month for fall planting. Try crown imperial (Fritillaria imperialis)—it grows 3 feet tall, with red, orange, or yellow blooms. 

In every area except the interior Rogue River Valley, plant lettuce, salad blends, and radishes. In milder zones on both sides of the Cascades, plant cabbage, Chinese cabbage, and kohlrabi. West of the Cascades, also plant beets, potatoes, and Swiss chard; sow peas along the coast and around Puget Sound. 

Continue to enjoy salads in early fall by adding leafy greens to your beds now. 

Harvest 

Green Beans

Thomas J. Story

Pick green beans before they mature and dry, or they’ll stop bearing; harvest summer squash when it’s small and tender; dig new potatoes when plants flower; and unearth mature spuds as plants die. 

Gather figs when their necks bend or if their sides start to split. Don’t leave overripe casualties on the tree or the ground—they can attract pesky yellow jackets. 

Maintain 

Remove vertical sprouts on apple and pear trees as soon as they appear. Such summer pruning doesn’t stimulate as much regrowth as winter pruning. 

You can rejuvenate many groundcovers (basket-of-gold, ivy, lithodora, and Phlox subulata, for example) by shearing with a rotary mower adjusted to a high cut setting. Then fertilize, water, and bait for slugs. 

In early September (earlier in Alaska and the mountains) over-seed worn or damaged parts of the lawn to make it whole for winter. Just scratch up the soil surface, scatter seed, cover with a 1⁄4-inch layer of compost or sifted soil, and keep it moist until new grass emerges. 

Protect 

Earwigs feed on flowers and vegetables, but also eat aphids, insect larvae, and snails. If they get out of hand, put newspaper rolls around affected plants at dusk, and discard them (with occupying earwigs) at dawn. 

Check houseplants for aphids, mealybugs, mites, and scale insects. In a shaded spot outdoors, hose off dusty leaves and treat with spray-on or systemic pesticide. 

Southwest 

Plant 

For an unusual shrub that’s well adapted to low-desert conditions, try puzzle bush (Ehretia rigida). Named for its dense tangle of cascading branches, it reaches more than 15 feet tall and wide and sports light blue flowers that have a slightly sweet scent. 

For fragrance, try beebrush (Aloysia gratissima) for its potent vanilla-scented florets on an airy 10-foot-tall shrub. Or look for creosote bush (Larrea tridentata)—it has tiny yellow flowers, plus leaves that exude a distinctive scent after desert storms. Both are natives with rangy habits, so be sure to give them plenty of room and site them at the wild margins of a garden. 

Harvest 

Cantaloupe

Thomas J. Story

Pick melons as they ripen. A cantaloupe is ripe when the veins on the skin become thick and the flesh underneath turns from green to gold. For ‘Crenshaw’ melon and honeydew, test for soft spots where the stem enters the fruit. For watermelon, look for several dried tendrils near where the fruit is attached to the vine. Also, most ripe melons of all varieties will separate from the vine without undue tugging.

When the fruit of the Engelmann’s prickly-pear cactus turns deep red, remove it with tongs, avoiding the spines. Ripe fruit will easily separate from the pads. Wash fruit, purée, strain juice through cheesecloth, and freeze in ice cube trays for later use in margaritas, agua fresca, and lemonade. Other prickly-pear varieties with edible fruit include the dinner plate (Opuntia robusta) and the Indian fig (O. ficus-indica). 

Maintain 

Toward the end of the warm season, prune cactus, including prickly pear, to maintain a compact shape. Using a long-handled saw, tongs, or a regular shovel, cut, pry, or knock off excess growth at the joints. Remember not to handle the pads, which are covered with hairlike spines called glochids. Collect pads and stems in a cardboard box for safe transfer to the trash. 

Rejuvenate tired and leggy tomatoes by pruning them back by two-thirds to encourage new growth and fruit set in late summer and fall. Weekly additions of balanced organic fertilizer will also increase yields. 

Protect 

Keep birds from eating maturing grapes by covering individual clusters of fruit with paper bags. Never use plastic bags, as they will cause the fruit to rot. 

Stake newly planted trees to withstand monsoon winds. Stakes should be temporary—remove them after one or two growing seasons. 

Control cochineal scale—a bug that causes fuzzy white dots on prickly-pear pads—by washing them off with a blast of water. Repeat as needed until the spots disappear. 

Southern California 

Plant 

Jump-start your cool-season vegetable garden by sowing seeds of celery or members of the cabbage family—including broccoli, brussels sprouts, cabbage, cauliflower, kale, and kohlrabi—in small containers. Plant the seedlings in the ground in October. 

Do any transplanting in the late afternoon or evening. That way, plants have the night to begin to recover and establish their roots before they’re hit with a full day of sun and heat. 

Seed bulb onions now for green onions throughout the winter and small bulbs in late spring. 

Harvest 

Harvest corn when silks go brown and ears are full. Pull back the husk to expose a full-grown kernel, then push your thumbnail into it. If the juice is clear, the corn is not ready; if milky, the corn is ripe for picking. If the kernel is dry, you’ve waited too long. 

Freeze excess vine-ripened tomatoes for winter use. After washing them, cut out the core, cut them into quarters, and place them on a cookie sheet so the pieces don’t touch. When they’re frozen, transfer them to bags or containers for use as desired. The peel will slip off easily when the tomato pieces begin to thaw. 

Pick ripe beans, cucumbers, eggplants, peppers, squash, and tomatoes at least every other day to encourage further production. 

Maintain 

At dusk on hot days, spritz foliage of native plants such as Fremontodendron with water from the hose as if a brief shower had dampened leaves and settled dust. Even species that die if irrigated in summer can safely absorb moisture through their leaves. 

For continuous rose bloom through fall, prune spent blooms weekly. Prune down to the first five-part leaf or a bit farther to gently shape the plant; then feed lightly and water. 

Protect 

Guard begonia, hibiscus, and passion vine against giant whitefly, which appears as a waxy, cobweblike infestation, by spreading a layer of dry earthworm castings 1 to 2 inches thick over their roots. Water and fertilize as usual. With this treatment, container-grown cane and ‘Richmondensis’ begonias should be pest-free in a few weeks. Additional applications may be needed for plants in the ground. 

Place ripening melons onto upside-down aluminum pie pans or metal cans to keep them off damp soil, preventing rot. Additionally, the reflected heat and light help the fruits ripen evenly and faster than they do when shaded by foliage. 

Mountains 

Plant 

Plant starts of broccoli, cauliflower, and kale, while sowing seeds of arugula, beets, bush peas, cabbage, endive, mustard, and spinach in the garden for fall harvest. 

Attract butterflies by adding tall sedums to your flower beds. These tough succulents thrive in heat and sun and come back every year. Good choices include brick-colored ‘Autumn Fire’, pink-flowered ‘Matrona’ and ‘Pink Bomb’, variegated ‘Frosty Morn’ and ‘Mediovariegatum’, and purple-leafed ‘Maestro’ and ‘Purple Emperor’. 

For brilliant scarlet-orange fall foliage, try a fragrant sumac like Rhusaromatica ‘Gro-Low’. A small, drought-tolerant shrub, it matures to 3 to 5 feet tall and at least 5 feet wide and thrives in full sun or partial shade. Enjoy yellow blossoms in the spring followed by red fruit in the summer months. 

Harvest 

Check beans daily and pick when pods are formed but before beans swell. Frequent harvesting keeps the beans producing and increases yield. 

Pick sweet peppers when they reach 3 to 4 inches. Remove ripe fruit frequently to encourage more production. 

Maintain 

Pavement ants undermine the stability of pavers laid on sand and form small dirt mounds on the surface. After sweeping up the soil, pour boiling water into the cracks. Sprinkle cinnamon on their nest sites to discourage ants from moving back in. 

Go through your garden once a day and snip off any flowers that are past their peak. Regular deadheading stimulates flowers to produce more blossoms. 

Never mow more than one-third of the height of your grass in hot weather. For most turf varieties, raise the blade on your lawn mower to 2 1⁄2 to 3 inches to ensure that leaves provide shade for the soil and any exposed roots. 

Protect 

Japanese beetles can do serious damage to gardens. The adults, which are 1⁄2 inch long and metallic colored, eat the flowers and leaves of many plants. Control these pests by knocking them into a bucket of soapy water. For large infestations, spray with a neem product that contains azadirachtin. 

If stems and leaves suddenly wilt and die on pumpkins or winter gourds, look for squash bugs on the underside of leaves. To control, drop them into a bucket of soapy water. 


This Story Came From the Fall 2020 Camping Issue—Read It Here!

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