Sun protection and irrigation lead off garden checklist during August heat

For The Union-Tribune

Now we are into the heat — real heat. Garden early in the day and late in the afternoon to stay out of the sun. Water, but not too much. Enjoy the cool evenings as time to rest and socialize. This is my favorite time of year to sit outside with my favorite people, after the sun goes down.

Stay safe in the sun

• The sun and heat peak this time of year. Protect yourself by gardening early morning and late afternoon. Try to stay indoors or in the shade during midday.

• Slather your skin with sunscreen. Wear long sleeves or “farmer’s sleeves,” plus a wide-brimmed hat to protect your face and scalp.

• The tops of your hands and feet are often forgotten when it comes to sun protection. Use a thick, zinc-based sunscreen. I also wear lightweight fingerless gloves/hand covers (helpful in the car too, for your hand next to the open window).

• Drink plenty of water, iced tea, juice and other nonalcoholic liquids through the day. Save the beer and margaritas for after sunset.

Irrigation

• 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 months for irrigation management. Turn on zones one by one, and:

– Check for breaks, leaks and clogged emitters. Flag problems so you can find them and fix them after you turn off the water.

– Flush lines — turn on each zone one at a time. 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 valves and lines.

– Check overhead spray (if you haven’t yet converted to drip) for broken lines, broken heads, pushed-over heads, misdirected heads, etc.

• Collect water as it warms in your shower or sink. Use that water on plants that need a little extra.

• For ornamental plants, water on a bed-by-bed basis. How often to water? Download a copy of my “Canary Test”  at tinyurl.com/canarytestgiveaway

Vegetables

• Plant a last round of summer vegetable seedlings at the beginning of the month using “early season” and “short season” varieties. These varieties ripen fruits fastest — from seed or seedling to harvest.

• How are your tomatoes this year? If you struggle with tomatoes or simply want to up your tomato game, download my tomato growing guide  at nanstermangardenschool.com/how-to-grow-tomatoes.

• Harvest squash, tomatoes, eggplants, peppers, etc. as they ripen. The more you pick, the longer plants produce.

• Harvest cucumbers and eggplants before they turn yellow; pick zucchini before they reach rolling-pin size.

• Harvest young loofa to cook like zucchini; leave them until the vine dies to use them as sponges.

• Store tomatoes in a single layer on the countertop or fruit basket rather than in the refrigerator. Sit them stem-end down to prevent mold from developing where the stem connected.

• Harvest pumpkins, melons and winter squash when the stems connected to the fruits turn the color of straw and pull away.

• Extra tomatoes? Wash, dry, then freeze them whole in zip-top bags. Or slather in olive oil, garlic and oregano, then dehydrate to raisin-dry. Read how  at bit.ly/2manytomatoes.

• Remove yellow and browning squash and cucumber leaves. Don’t panic when older leaves die. These are annual plants. Their leaves only last a season, at most.

• To prune or not to prune tomatoes? NOT. Leaves are the plants’ energy engines. Their chlorophyll (the green pigment) is where photosynthesis — energy production — happens. More leaves = more energy = more flowers = more fruits.

• Removing a plant’s leaves reduces the plant’s ability to make fruits.

• Powdery mildew got your veggies? The substance appears to be a fine white powdery coat on squash leaves, tomato leaves, pumpkin leaves and so on. Humid weather and overly dense plants create the ideal conditions for powdery mildew spores to settle on leaves and spread. While you wait for heat and dry conditions to dry out the mildew spores:

– For bad infections of very dense plants, selectively remove inner branches to increase air circulation. Don’t over prune, however. Opening up plants too much exposes the fruit to sunburn.

– Rinse leaves with just water, early enough for them to dry completely by midday.

– Cut off badly infected and yellowing leaves. Have a bucket handy and put each one directly into the bucket, then dump the bucket in the greenwaste and rinse the bucket with water. If you carry infected leaves through the garden, you risk spreading powdery mildew spores to other plants. Use a light hand so you don’t expose fruits to sunburn.

• Soft brown spots on the bottom ends of tomatoes, peppers or squash are blossom end rot. Despite what you read, adding calcium to the soil is not the solution — our soils have more than enough calcium already. Instead, even out soil moisture so plants can take up the available calcium. Check the soil around your plants. It should be damp, not wet, at all times. Don’t bother adding eggshells, antacids, etc. to the soil. They won’t solve the problem.

• Prepare for fall. Order seeds for fall crops now, so you are ready to start planting in September, October and November:

– Leafy greens like lettuce, spinach and chard.

– Cold-weather crops including broccoli, cabbage, rapini, cauliflower and kohlrabi.

– Root vegetables such as beets, carrots, radishes and rutabagas.

– Cover crops if you don’t intend to grow a winter garden.

Fruit trees

• Irrigation checkup:

– The goal of irrigation is to deliver water to shallow surface roots as well as to deep roots.

– Irrigate fruit trees with inline drip laid out in concentric circles. Start the smallest circle about 10 inches from the trunk of mature trees, 6 inches from the trunks of newly planted trees. 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. Make sure water penetrates to the deep roots in addition to wetting surface roots. Wait until the soil feels almost dry, finger deep, then water again.

• Mulch to keep water in the soil and keep tree roots hydrated. Spread a 3- or 4-inch-thick layer of wood-based mulch (not bark chunks) over the entire planting area, including over the drip irrigation.

• Feed all fruit trees with organic fertilizer designed for each type of tree (stone fruits, citrus and avocado, etc.) Pull the mulch back and sprinkle fertilizer onto the soil around the drip lines, then hand water to help the fertilizer penetrate into the soil. Or, apply a liquid organic fertilizer. When you are done, replace the mulch.

• Eyes on avocados:

– Let avocado leaves accumulate under the tree. Leaves keep the soil moist and cool. As they break down, their nutrients recycle back into the tree.

– Don’t dig, plant or rake under avocado trees. Their shallow surface roots are easily damaged. Fallen leaves protect those roots.

– Leave the lower branches to form “low skirts.” Their leaves shade the bark and protect it from sunburn.

– Paint the bark of young trees to prevent sunburn until the trees are old enough to have dense branches. Use orchard paint or interior latex paint mixed 50/50 with water.

Deciduous fruits

• Fig alert:- Sadly, black fig fly continues to destroy fig crops. The female bores into the fig to lay its eggs, which hatch out as larvae inside the fruit and eat the unripe insides before burrowing their way out. In the process, the fruits stop ripening, turn brown and drop while still hard and small. While scientists work on a solution, cover young developing fruits with drawstring mesh bags. Remove fruits immediately as they show signs of infection.

– Stop the spread — keep all figs on your property; don’t move them.

– Report black fig flies to the California Department of Food and Agriculture pest hotline, 1-800-491-1899 or cdfa.ca.gov/plant/reportapest.

• Those drawstring mesh bags also help keep out rats, fig beetles and other critters.

• Color only suggests that fruits are ripe. Harvest:

– Stone fruits when they begin to soften.

– Apples when they taste good.

– 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 winter, you’ll prune again for shape.

• Collect and compost fallen fruits, damaged fruits, overripe and rotting fruits.

• Sample grapes for ripeness. When they taste sweet, pick!

Ornamental plants

• If you love springtime bulbs, now’s the time to plant. Spring-blooming bulbs are dormant now, making it the best time to plant California native mariposa lilies, South African harlequin flower, baboon flower, species gladiolus, etc. Learn more by watching my on-demand class “Flower Power! Fabulous Bulbs for California Gardens” at bit.ly/CaliforniaFlowerBulbs.

• This is prime time to solarize your lawn and other areas of the garden covered in nuisance weeds or soil diseases. Here’s the basic approach:

– Mow the grass or cut the weeds very, very short.

– Irrigate to saturate the soil at least 6 inches deep.

– Cover the lawn or garden bed completely with 1- or 2-ml thick sheets of clear plastic. Overlap seams if you need extra sheets to cover the whole space. Weigh down the edges.

– Turn the sprinklers off, then wait six to eight weeks as the soil superheats.

– When the lawn or weeds turn straw-colored, they are dead.

– Learn more from my on-demand class, “Bye Bye Grass: How to Remove Your Lawn,” at bit.ly/ByeGrass.

• Check at bewaterwise.com/turf-replacement-program.html for the latest cash for grass turf rebate program, sponsored by your local water retailers and wholesalers.

• Summer is a tricky time for watering established native shrubs and trees, as well as drought tolerant plants from South Africa, Chile and Australia. All of these plants are adapted to dry summers. Once established, water these plants once a month or less, depending on your location. If leaves start to brown, do not water; chances are, they’ve been overwatered. Warm, wet soil encourages fungi that attack the plants’ roots. Wait to water until winter, to ensure that plants survive.

• Switch old-style spray sprinklers to high efficiency in-line drip irrigation. Water early early in the morning when the air and soil are cool.

• Deep soak newly planted natives no more than once every four weeks through the heat. Spritz them lightly in between deep waterings. Waterlogged soil can kill these plants.

• Leaves covered in dense, disorganized webs likely have spider mites, tiny orange spider-looking bugs. Spider mites infest leaves and stems of plants that are too dry and/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 Bug Blaster hose end sprayer to blast the upper and undersides of the leaves with water and blow the critters away.

• 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.

Houseplants

• Keep an eye out for mealybug — small, very white, fuzzy patches spots on plant leaves and stems. Smoosh with your fingers, spritz them off with a sharp stream of water, or spray with diluted 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 can 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 far better planted in the ground, or in very large containers outside.

Garden critters

• Snakes and spiders might scare you, but they are important garden helpers:

• Spiders eat common garden and household pests like 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 mosquitofish to ponds.

• Add Mosquito Bits granules to the center of bromeliads where water collects, as well as to ponds, rain barrels, etc.

• Screen, then securely close rainbarrels to help keep mosquitoes from breeding, too. Remember to welcome the spiders that eat mosquitoes!

• Worms and caterpillars nibble leaves but their damage is balanced by the critical role they play in your garden’s ecosystem. They are essential food for native birds and lizards. If they cause significant damage, pick worms/caterpillars off your plants and place on a table or sidewalk where birds or lizards can see (and eat) them easily.

August garden events

Attend the Carnivorous Society’s annual plant sale on Aug. 2 and 3 in room 101, Casa del Prado, Balboa Park. Doors open to the public at 10 a.m. on both days. Learn more at sandiegocarnivorousplantsociety.com.

Sterman is a garden designer, journalist and the host of “A Growing Passion” on public television. She runs Nan Sterman’s Garden School at waterwisegardener.com.