This week is the last chance to sow frost hardy lettuce, corn salad and arugula in the garden outdoors. If you have coldframes or are sowing in an unheated greenhouse you can get away with waiting another week or two, but given the generally cool season, I would still sow as soon as possible. With the high daytime temperatures forecast for the next few days, be sure to shade new seedbeds so that seeds and seedlings don’t fry. By now, with gaps opening up in the garden where sweet corn, onions, early potatoes, etc. have been harvested, you should be able to find lots of open spots to sow seeds. You can also sow corn salad and lettuce under tomatoes, peppers, pole beans and other crops that will be finished in October—just pull back mulches and scatter the seeds on the soil. Corn salad simply won’t germinate in warm soil, but when it is a bit cooler you will suddenly see the soil covered with seedlings.
Powdery mildew, that whitish dusting seen on leaves of squash and other plants, is spreading quickly in the humid weather. This group of fungi has spores that can’t germinate in the presence of water so rainfall and overhead watering suppress infections. During dry, but humid, weather the fungi spread quickly, especially on older leaves, which are less able to fight off infection than vigorous new leaves. While powdery mildew appears on a variety of plants at this time of year, the fungi are different species, so the mildew on peas or chard isn’t the same one as on squash or roses. Choosing powdery mildew resistant varieties of cucumbers, squash, peas, etc. where available is always a good idea, but you can also stave off infection by keeping plants growing vigorously. If plants need an end of season boost, water them weekly with a liquid fertilizer, such as diluted fish fertilizer or ‘tea’ made by soaking fish compost or horse manure in a bucket of water for a day or two to extract the nitrogen/ You can also slow the rate of infection by spraying the leaves with water at midday several times a week to prevent spores from germinating. Don’t pick off infected leaves: you can’t control the disease that way and all you are going is depriving the plant of leaf area that could still be helping to feed the plant. [More on powdery mildew in last year’s message for Aug. 28: http://www.lindagilkeson.ca/gardening_tips.html ].
– Right now, check whether carrots, beets and other crops sown in the July and August need to be thinned and weeded. I find that carrots under insect netting are easy to forget about and mine need to be thinned again this week to ensure they reach full size in the next month. And those baby carrot thinnings are so delicious!
-Check apple and winter pear trees (summer pears, such as Bartletts, should all be picked by now) for branches weighed down with fruit. A wind storm at this time of year can do a lot of damage so prop branches up or tie them to temporary stakes to support the weight of the fruit until it is harvested.
-Pinch off the new flowers on vining (indeterminate) tomatoes to allow to plants put their energy into ripening the fruit already on the plant. Unless plants are in a greenhouse, fruit setting this late won’t have time to ripen. Remember that tomatoes ripen perfectly well off the vine once they have turned light green so you will be able to pick and ripen late tomatoes indoors when we run out of ripening season out in the garden.
-Make a note to pinch or snip out the growing tips of Brussels sprouts plants by the end of September to force development of sprouts along the stems. This is especially important for plants that are still short, because it will allow you to get some crop. If your Br. sprouts are 4-5 feet tall at this point, pinching out the tips is probably unnecessary (I still do it, though). Br. sprouts plants should be staked securely because they are top heavy and easily toppled by wind.
Year Round Harvest courses are a go for 2021:
My course starting in January at the Horticulture Centre of the Pacific will be delivered once a month for 10 months until October. We will meet face-to-face in months when we can book the large pavilion, which permits us to follow physical distancing guidelines. We will hold classes by Zoom videoconferencing when the pavilion is not available and any time it is necessary depending on the covid situation. We are taking fewer students this year so if you interested, do get on the interest list for registration ASAP: https://hcp.ca/year-round-harvest/ or call HCP directly: 250-479-6162.
The Year Round Harvest course for Salt Spring will also be a hybrid delivery model with videoconferencing some months and face-to-face in a local venue when possible. I already have more than enough people on the interest list to fill the class, but contact me directly if you want to try to for the wait list: email@example.com