August 6, 2023: Last sowing for winter crops

From Linda Gilkeson:

With temperatures dropping a bit and the possibility of rain showers early in the week, right now is the perfect time to sow seeds of arugula and other hardy greens such as mizuna, collards, kale, Chinese cabbages/Napa cabbage, leaf mustards, mustard spinach, broccoli raab, winter radishes/daikon. These crops must be sown within the next 10 days to have enough time to produce a crop that can be harvested this winter. Veggie seedlings can be transplanted any time this month. As long-time readers know, August 12 is Spinach Day at my house: the timing that works best in my garden to seed spinach directly in the garden for a fall through spring crop. August-sown spinach plants remain in the garden over the winter and will go on to produce a big crop of new leaves crop in the early spring. There is one last, late August to early September planting window, when corn salad, winter lettuce and arugula can be sown.

After that unusually dry May and the dry weather that has featured a lot of fairly hot days and drying winds, it has been very hard to keep vegetables and fruit sufficiently watered (especially since most of south coastal BC is currently subject to restrictions on tap water use). This year, despite irrigation, my figs and plums are smaller than usual as are cool weather plants such as broccoli—my summer cauliflower has been hopeless as they just can’t take the stress! Keep adding mulch around plants to maintain a thick layer: it really makes a difference in how well plants grow to protect their roots from high temperatures and it also conserves water. Do what you can within your water allocation to keep things watered, including collecting household water from showers, washing veggies, rinsing dishes, etc., to use in the garden.

At this time of year, after you sow seeds and water them, it is essential to shade the seedbed to cool the soil and keep it evenly moist. Anything can be used for shade, including burlap, newspaper, old sheets, white plastic bags (cut open compost or potting soil bags and lay them white side up). Seeds germinate quickly so check every morning and remove the cover at the first sign of sprouts. Summer seedlings are extremely vulnerable to heat injury so make sure they have plenty of water and protect them from hot sun with 50% shade cloth, lathwork screens or other shading until they are deeply rooted. As soon as possible, work a fine mulch around the little plants.

For plants in the mustard/cabbage family (daikon and hardy greens listed in the first sentence, above) cover seedbeds with insect netting or floating row cover to prevent attack by cabbage root maggot flies. In many areas this pest will likely have a third generation this year, which means very high numbers present in late August and September. Once maggots are feeding in the roots, nothing can be done to save the attacked plants, but barriers work very well to prevent the adult flies from laying eggs on plants in the first place. The barrier has to be in place before the shoots appears (lay the shade cloth on top of the insect barrier to shade the seedbeds).

Irrigation note: Recently I have been sent a number of photos of split root crops, sun scalded leaves, blossom end rot and other damage that results when the soil is allowed to get too dry between irrigation cycles. Check that you are watering often enough to maintain moist soil. Split roots happen when the soil is allowed to get too dry and roots take up water too fast when they are watered. The same conditions cause blossom end rot in tomatoes and cause leaves to burn in the sun during the period when the soil is too dry. It might be necessary to water more often or more efficiently, perhaps using less water at one time to ensure more even soil moisture (and, as always: mulch, mulch, mulch!).

my web site:

Also on my web site you can see hundreds of photos of pests, beneficial insects, diseases and disorders to help you identify problems. I have also made pdfs available of presentations on growing vegetable seedlings, saving seeds, climate resilient gardens, the issue of global loss of insects—and there is even a pdf on how to identify coastal butterflies.

Republished with permission from Linda Gilkeson’s Gardening Tips. See Linda’s website to sign up for her newsletter, purchase books, access free presentations and identify pests and diseases which may affect West Coast gardens.