Tasks to tackle in the August garden, from frequent harvesting to thoughtful watering
Summer is the area’s most challenging season for gardeners, with heat and pests adding to chores.
It’s summer — the garden’s harshest and most challenging season of the year. It’s Southern California’s gardening equivalent to winter in most parts of the country.
Pay close attention to how much, how long and how often you water different kinds of plants in your garden.
Your goal is to water just right — not too much, not too little — for each.
Stay safe in the sun
● Garden in the early morning and late afternoon.
● Wear long sleeves and a hat, and slather your skin with sunscreen.
● Protect the tops of your hands with lightweight fingerless gloves or hand covers.
● Use mosquito repellent.
● Drink plenty of water, iced tea and juice (not alcohol) throughout the day.
● Because of the long, cool spring, many summer vegetables are ripening later than usual. Be patient. It’s just the weather.
● What’s a vegetable and what’s a fruit? A fruit is any edible part of a plant that has seeds: tomatoes, cucumbers, pumpkins, peppers, eggplants, berries, etc. Any edible plant part without seeds is a vegetable: kale (leaves), radish (roots), artichoke (buds), rhubarb (stems) and more.
● Harvest tomatoes, eggplants, peppers, etc., as they ripen. The more you pick, the longer plants produce. Pick before critters beat you to the produce.
● Harvest cucumbers before they yellow and zucchini before they are the size of baseball bats.
● Harvest young loofa to eat like zucchini. To use loofa as bath sponges, leave the fruits on the vine until the entire vine — and fruits — turn brown and dry out.
● Store tomatoes in a single layer on the countertop or fruit basket rather than in the refrigerator. Set them stem-end down to keep them fresh.
● Extra tomatoes? Wash, dry and freeze them whole in zip-top bags. Or slather them in olive oil, garlic and oregano, then dehydrate them to raisin-dry.
● Harvest pumpkins, melons and winter squash when the stems that connect to the fruits turn the color of straw and pull away from the fruit.
● Remove yellow and browning leaves from vegetable plants. Don’t panic when older leaves die. Leaves don’t last forever, especially not with annual plants.
● To prune or not to prune? Not. Leaves are the plants’ energy centers. Their chlorophyll (the green pigment) is where photosynthesis — energy production — happens. More leaves = more energy = more flowers = more fruits. Removing leaves reduces the plant’s ability to make fruits.
● However, too-dense branches create humid conditions that encourage powdery mildew. If you find powdery mildew, selectively remove branches to increase air circulation in the center of the plants.
● Soft brown spots on the bottom ends of tomatoes, peppers or squash are blossom end rot. Solve the problem by evening out irrigation so the soil is consistently damp (not wet) all the time. Don’t bother adding eggshells, antacids or other sources of calcium to the soil. They won’t solve the problem.
● Plant a last round of summer vegetable seedlings at the beginning of the month using “early season” and “short season” varieties. They are fastest from seed (or seedling) to harvest.
● Prepare for fall. Order cool-season vegetable seeds and fall cover-crop seeds now for best selection. Sow seeds starting in September, but purchase them now.
● Pepper plant mix-up? In what’s been dubbed Jalapenogate, there was a massive mislabeling of pepper seeds at the wholesale level this year. The mislabeled seeds were sold to home gardeners and seedling growers alike. Gardeners report planting green jalapenos but harvesting yellow ones, or planting “Hungarian sweet wax” and harvesting pale green “diamond” bell peppers, or planting “purple beauty” bells but harvesting “Hungarian hot wax” and so on. Did it happen to you? Blame it on Jalapenogate.
● Is it time to add more irrigation to your fruit trees? The irrigation needs to cover the entire soil surface under the trees’ canopy, plus a few feet beyond. That’s where you’ll find most of the roots that take up water. Irrigate the trees with in-line drip laid out in concentric circles. Start the smallest circle about 10 inches from the trunk of mature trees, six inches from the trunks of those newly planted. Place the next circle a foot out from the first and continue adding circles a foot apart. The widest circle should be a foot or two beyond the widest part of the canopy.
● Run fruit tree irrigation for an hour or more each time so water penetrates to the deep roots. Wait until the soil feels almost dry before watering again.
● Mulch is crucial for holding in moisture. Spread a 3-inch-thick layer of wood-based mulch across the entire planting bed, covering the drip irrigation.
● Feed all fruit trees with organic fertilizer formulated for each type of tree (stone fruits, citrus and avocado, etc.). Pull the mulch back and sprinkle granular fertilizer onto the soil around the drip lines and hand-water it in. Or wet the soil with liquid fertilizer. Then replace the mulch.
● Let avocado leaves accumulate under the tree. Leaves keep the soil moist and cool. As they break down, the nutrients recycle back into the tree.
● Don’t dig, plant or rake under avocado trees. Their shallow surface roots are easily damaged.
● Leave the lower branches to form “low skirts.” Their leaves protect the sensitive bark from sunburn.
● Paint the bark of young trees that haven’t yet developed dense branches. Use orchard paint or interior latex paint mixed 50/50 with water.
● Cover fruits with drawstring mesh bags to keep rats, fig beetles and other critters away.
● Don’t rely on color to tell you when fruits are ripe: Harvest stone fruits when they begin to soften; harvest apples when they taste good; harvest figs when they are super soft. Figs do not ripen off the tree, so don’t pick them early.
● Summer-prune deciduous fruit trees. Shorten the soft new growth so branches — and next year’s fruits — stay within reach. In the winter, you’ll prune again for shape.
● Collect and compost fallen, damaged, overripe and rotting fruits.
● Pit and freeze extra stone fruits, raw or cooked. Later, thaw them to use in pies, crumbles, compotes, etc.
● Ferment stone fruits to make fruit wine, vinegar, kombucha and more.
● Sample grapes for ripeness. When they taste sweet, pick them.
● Plan, don’t plant. Fall and winter are the planting months for ornamentals. Those planted now will be very hard to keep alive.
● This is prime time to solarize your lawn and any other areas of the garden that have nuisance weeds or soil diseases. Here’s the basic approach:
1. Mow the grass or cut the weeds very short.
2. Irrigate to saturate the soil at least 6 inches deep.
3. Cover the lawn or garden bed completely with 1- or 2-millimeter-thick sheets of clear plastic. Overlap the seams if you need extra sheets to cover the whole space. Weigh down the edges.
4. Turn the sprinklers off, then wait six to eight weeks as the soil superheats.
5. When the lawn or weeds turn straw-colored, they are dead.
● Watering established native shrubs and trees, as well as those from South Africa, Chile and Australia, is tricky. Like California natives, these plants are adapted to no summer rain. Water established plants once a month or less, depending on your location. If their leaves start to brown, do not water. Chances are they’ve been overwatered. Warm, wet soil encourages types of fungi that attack the plants’ roots. Wait until winter to see whether the plants survived.
● When you do water, use in-line drip irrigation and run it at night, when the air and soil are coolest.
● Deep-soak newly planted natives no more than once every four weeks and spritz lightly and let the soil drain between deep waterings. Waterlogged soil can kill these plants.
● Leaves covered in dense webs probably have spider mites — tiny orange spider-looking bugs that infest plants that are too dry or whose leaves are covered in dust. Their natural enemies live in the garden, too, so don’t spray with any kind of pesticide, oil or insecticidal soap. Instead, use a hose sprayer on the upper and undersides of the leaves.
● Remove spent blooms on roses to encourage fall flowers. Fertilize with organic rose food (follow label directions). Water deeply periodically.
● Plumeria are at peak bloom, so shop for your favorites now.
● Water hanging baskets every few days, since they dry out quickly in our climate.
● Keep an eye out for scale — oval brown spots on plant stems. Check the plant stems for juvenile scale, which are pale yellow, almost translucent and smaller than the adults. Scrape them off with your fingernails or dab with a cotton swab dipped in rubbing alcohol.
● Give houseplants a summer vacation by putting them outside under the shady branches of a tree or under protective eaves. Allow your garden predators to keep pests under control. The breeze will blow pests away, too.
● Not all plants sold as houseplants are actually suited to living indoors. Trees, succulents, herbs and more look sweet in your kitchen or living room but grow much better planted in the soil or in very large containers outside.
● Are you watering according to your water district’s current restrictions? Check its website for how often and how long you should run overhead sprinklers. Most restrictions don’t apply to drip irrigation or hand-watering.
● Droopy leaves in the morning are a signal that a plant needs water — droopy leaves in the afternoon are not.
● The hot months are the most important for irrigation management. Turn on your zones one by one and:
1. Check for breaks, leaks and clogged emitters. Flag problems so you can find them once the water is off.
2. Flush lines — turn on each zone, then open the flush valve for each bed or open the end of the lowest-elevation line in a bed. Let the water flush through for a few minutes before closing the valves and lines.
3. Check overhead spray (if you haven’t yet converted to drip) for broken lines, broken, pushed-over or misdirected heads, etc.
● Collect water in your shower or sink and water plants that need a little extra.
● In the vegetable garden:
1. Water soil, not leaves. Wet leaves are susceptible to diseases like powdery mildew.
2. Water early in the morning when the soil is dry. Keep the soil evenly damp, not wet.
3. Mulch with a 3-inch layer of straw (not hay) to slow water loss.
● For ornamental plants, water on a bed-by-bed basis. To see how often to water, download my “Canary Test” at tinyurl.com/canarytestgiveaway.
Snakes and spiders might be scary, but they play an important role in your garden.
● Spiders eat common garden (and household) pests such as gnats and mosquitoes, aphids, wasps, leafhoppers, even june bugs.
● Gopher snakes eat gophers. Rattlesnakes eat rabbits, gophers and squirrels. King snakes eat rodents, too.
● Tiny bug bites around your ankles and legs during the day could be from Aedes mosquitoes. These tiny insects lay their eggs in small puddles of standing water indoors and out. Inspect your property weekly. Empty the dishes under your potted plants. Add mosquito fish to ponds. Add mosquito granules to the center of bromeliads where water collects. Screen, then securely close rain barrels to keep mosquitoes from breeding there. Remember to welcome the spiders that eat mosquitoes.
● Worms and caterpillars nibble leaves, but their damage is balanced by the crucial role they play in your garden’s ecosystem. They are essential food for native birds and a great way to attract birds to your garden. If they cause significant damage, pick them off your plants and place them on a table or sidewalk where birds can see them easily.
Nan Sterman is a garden designer, journalist and host of “A Growing Passion” on public television. She runs Nan Sterman’s Garden School at waterwisegardener.com. ◆
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