It’s been a cool, dry spring, but now, we can enjoy summer. Here’s to bare feet, shorts and sunscreen in the garden! It’s also time to put the lessons you learned from last year’s COVID-19 gardening to work.
Vegetable gardens
What we call “summer vegetables” are actually “summer fruits.” To botanists, any plant part that makes seeds is a fruit. So tomatoes, cucumbers, melons, peppers, eggplants, squash, okra and so on are all fruits.
Extend your harvest with succession planting. Start another round of tomatoes, cucumbers, squash, eggplants, basil and so on. The plants you start now — from seed or seedling — will produce into fall.
Make the next round of vegetables something new — a variety you haven’t planted before. I am fond of the round, scallop-edged patty pan squashes. They have a nutty flavor, especially when sliced thick and cooked on the grill.
White powder on vegetable leaves (especially squash, cucumbers and tomatoes) is powdery mildew that develops in humid air around the leaves. Selectively remove branches to open up the plant, and rinse the leaves with water to wash off spores. Be sure to wash leaves early in the day so they are dry long before nightfall. Otherwise, the mildew will get worse.
Problems with unpollinated tomato flowers? Honeybees don’t pollinate tomatoes. Instead, they are pollinated by wind or by large native bees like bumble bees and carpenter bees. The bees “buzz pollinate” the tomatoes, meaning that they vibrate their bodies to shake pollen from male parts of the tomato flower, then carry it to the next flower. You can be a big bee, by using the back of an old electric toothbrush to buzz the inside of one flower and then move to the next flower and “buzz” there, too. Do be gentle, though.
Some people mistakenly think that pruning off tomato suckers and branches force the plants to make more fruits. The opposite is true, since leaves make the energy the plants use to make flowers and fruits. So leave the leaves.
The only reason to prune tomato plants is to train them to a trellis or to remove selective branches for good air circulation and light penetration. Air circulation staves off mildew while light penetration helps power the plant and ripen fruits.
Removing lowest tomato branches does help keep hungry critters away from tomato fruits and prevents soil fungi from splashing onto leaves.
Light up your vegetable garden with another round of summer flowers like marigolds, zinnia, cosmos and sunflowers.
Mulch vegetable plants with a thick layer (3 or more inches) of straw — NOT hay.
Feed vegetable plants with an organic vegetable fertilizer. Pull the mulch back; sprinkle fertilizer over the soil, water, then replace the mulch. Add liquid fertilizer to your irrigation water — this process is called “fertigation” and can be done at low concentrations, every time you water. Use liquid fertilizer as a quick-fix foliar spray for plants showing signs of nutrient deficiency.
Skeletonized tomato leaves and tiny balls of green are evidence of tomato hornworms. Search for the green, white and black striped caterpillars on stems and backsides of leaves. Don’t be shy; pull the worms off the plants, and drop them into a container of water with a layer of vegetable oil on top.
Skeletonized sunflower and squash leaves could be attributed to tiny birds called lesser goldfinches. Don’t deter them, though, as they also eat aphids. Instead, plant enough to share.
Fruit trees
Enjoy peaches, apriums, plums and other stone fruits as they ripen. If you have extras, cut the fruits in half, remove the pits, and freeze for winter pies and crumbles.
If your harvest is overwhelming, share it with those in need. There are organizations that provide volunteer gleaners to pick and donate your fruit to food banks and other feeding programs which are so, so important right now. Find lists of gleaners through the San Diego Food System Alliance for San Diego County. If you have time to give, those same organizations to volunteer to be a gleaner.
If you have an unpicked orchard, Produce Good). This hunger relief agency brings a volunteer crew to the site for picking and then delivers the product to the local food bank.
Practice good garden hygiene to avoid attracting hungry birds, green fig beetles, squirrels, rats, etc. Harvest fruits as they ripen, before they rot. Clean up fallen fruits, too.
Fertilize fruit trees with organic fertilizer, following label directions. Water regularly and deeply during the fruiting and growing season.
Fertilize citrus and avocado with granular organic citrus and avocado food. Follow label directions.
Water citrus deeply once a week or so. Pomegranates, figs and pineapple guava are best watered every two weeks, depending on how hot it is and your garden’s location.
Ornamental plants
Drought-tolerant shrubs need little care this time of year. Clean out dead flowers and spent leaves. Keep them mulched and water deeply once every few weeks.
Water lawns no more than twice a week and switch to high-efficiency rotating sprinkler nozzles. Better yet, prepare now to remove the lawn next month by solarizing it.
Potted plants need more attention through summer. Fertilize nonsucculent potted plants with an all-purpose organic fertilizer (liquid indoors, liquid or granular outdoors), following label directions.
Potting soil dries out more quickly than dirt, so monitor the soil so you know how often it needs to be watered. Water slowly to saturate the entire pot, soil and all. Wait until the water drains out and then do it again.
Move sun-shy potted plants like fuchsia and orchid cactus (Epiphyllum) under the shade of a leafy tree or an east-facing eave.
Houseplants
Small black flies that circle potted plants are fungus gnats. They eat decaying organic matter and lay their eggs in the wet potting mix. Eliminate them by 1) watering much less and 2) covering the soil surface with an inch or two of rounded pebbles. That interrupts their access to the potting mix and, soon, they disappear.
Thrips cause tiny whitish spots on the top of leaves and tiny black spots underneath. The black spots are the thrips. Spray them off with water or, better yet, give your houseplants an outdoor vacation for a few weeks. Put them under the eaves or in another shaded spot and leave them while the natural predators feast on the pests.
Brown, crispy leaf edges usually result from too much salt residue in potting soil. Repot your plants into fresh potting soil (and a larger pot) and then leach the soil by letting water drip through for a few hours. Repeat a few times through the year.
Manage water
The U.S. Drought Monitor shows that we are back in drought, so pay attention to how you use water.
Don’t overwater your garden. Figure out the minimum amount it needs and then water just a little bit more.
Collect cold bath and shower water in a bucket. Use the water for potted plants, thirstier tropical fruits, and vegetables.
Mulch, mulch, mulch — but only if you have a drip irrigation system. If you have overhead irrigation, the water first has to saturate the mulch before it can reach the soil. This is another reason to switch to in-line drip irrigation.
Deep-water big trees once a month through summer once the temperatures get warm. Even drought-tolerant trees need a long drink.
As the heat builds, don’t be tempted to overwater protea, California native plants and plants from other dry regions of the world. These plants are adapted to dry summer conditions. They don’t need extra water, and in some cases, wet, warm soils can shorten their lives.
Sweep walkways and driveways instead of hosing them down.
Discover more California gardening, horticulture, agriculture and native plants by watching “A Growing ion,” Thursdays at 8:30 p.m. and Sundays at 11 a.m. on KPBS-TV in San Diego, or online everywhere, anytime at agrowingion.com.
Sterman is a waterwise garden designer and writer and the host of “A Growing ion” on KPBS television. More information is at agrowingion.com and waterwisegardener.com.
