Winter garden preparation, winter cauliflower seeds

Extreme weather driven by the changing climate is certainly hitting hard these days. We continue to get the wetter, colder weather consistent with a La Niña season, so brace for more of the same until spring. September, in particular, was a cooler than normal month, so you might have noticed that some late crops didn’t grow as much as they should have in the waning days of fall. I am disappointed in the size of my fall cabbages, for example. Hardy vegetables do grow a bit over the winter, however, and will pick up speed in early spring. If they are too small to harvest now, just leave them in the garden.

With all this rain, you might also notice that leaves of spinach, lettuce and Swiss chard have developed black blotches and ragged or decomposing leaf edges. The leaves of these plants are more delicate than leaves of cabbage or broccoli, which have waxy, water-repellent leaves. When rain, rain, and more rain, abrades the cuticle of leafy greens, the leaf tissue just breaks down. Such plants stay in better condition if they are protected from rainfall under the overhang of a roof, under a plastic tunnel or cold frame or in an unheated greenhouse. I find that continuous rainfall is more damaging to leafy greens than cold weather. The good news is that no matter how beat up the plants are by winter weather, the roots are usually fine, especially if you mulched around the plants to insulate the soil from frost. New growth will start from the roots in late February or March. The growth rate will pick up speed as the days warm up and you will be surprised at how robust and productive the new plants are. So don’t remove sad plants now, even if they are really ratty (if you have a “yard-cleaner-upper” type of spouse in the house, make sure they also know to leave the plants alone). You may also notice that some older leaves of chard, cabbage family and other hardy vegetables are turning yellow or dying back. Again, not to worry: Winter vegetables normally shed their oldest, least weather-hardy leaves at this time of year. I just pick off these funky leaves and drop them to the soil to add to the mulch.

Growth from overwintered plants

Finish mulching around plants now, but hold off on covering over the tops of root crops until there is a forecast of below-freezing weather. This often happens in early December; at this time it doesn’t look like any really cold weather is forecast through the end of November. Be prepared when it does get cold to heap a good layer of mulch right over the leaves of root crops (and, of course, finish any other mulching that needs doing). In previous messages I have written a lot about fall mulching so for more details, have a look at last month’s message, October 17 or at my November 7, 2019 message.

Prepare for cold protection: No matter how cold it gets, root crops protected under a thick mulch will be fine, but if/when, we get Arctic outbreaks this winter, be ready to cover above-ground plants. Temporary covers work fine—as long as you deploy them before the cold hits. I keep a pile of light tarps folded up in the garage, ready to go on short notice, along with a handy pile of good sized rocks to use as weights. Arctic outbreaks are usually accompanied by high winds so heavy anchors are necessary to keep tarps in place. When to cover: Cover hardy lettuce and other leafy greens when the forecast sounds like it might dip to -5oC [23oF] in your region or elevation. If it will be several degrees colder than that, then throw a tarp over winter broccoli and cauliflower, perhaps leeks and Brussels sprouts. Kale, parsley, corn salad and the really hardy varieties of leeks (e.g., ‘Unique’) and Br. sprouts (e.g., ‘Roodnerf’) don’t need to be covered, unless we get record breaking cold (which I wouldn’t bet against, given the way this year has gone….).

Temporary covers

Unheated greenhouses or tunnels: During cold snaps, when temperatures drop below freezing at night, it will be nearly as cold inside an unheated greenhouse as out in the garden. Therefore, be prepared to cover plants in the greenhouse with a tarp or to throw tarps over tunnels. It is also important to prevent greenhouses from overheating when the sun is shining, which usually is more of an issue after January. In February, my own greenhouse can easily reach 35oC [95oF] on a sunny day if I don’t open the vents--and that’s much too hot for hardy greens. Ideally, the difference in temperature between night and day should stay within 15 degrees range to avoid stressing leaves and causing soft, weak growth that is susceptible to frost injury and diseases. If it is getting down to freezing at night, then ventilate to keep daytime temperatures to a maximum 15oC (60oF) for the health of plants.

Electrify your lemon tree. If you are growing citrus outdoors and haven’t installed winter protection yet, it is past time to do that. Thread plumbing heating cables or strings of incandescent Christmas lights through the branches to supply enough heat to keep flower buds and fruit from freezing. The heating cables are sold at hardware stores; they have built-in thermostats that automatically turn on when temperatures drop to a degree or two above freezing. You will need a thermostat to control Christmas lights if you want lights to turn on automatically when temperature drops. After installing heating cables in my lemon and lime trees, I wrap a tube of heavy, clear plastic around each tree and then use several layers of floating row cover over the top opening to allow air circulation. The whole thing is secured with sturdy bulldog clips against winter winds. In warmer or more protected locations, covering the trees with heavy row cover fabric (‘fleece’) instead of plastic, works fine.

Seed ordering: The run on everything to do with gardening continued this year, so once again you might want to lay in garden supplies, seeds and soil amendments sooner rather than later. At least some Seedy Saturdays are resuming in 2022 and these are often good places to get seeds, especially from local companies. Keep checking the Seeds of Diversity website for communities offering Seedy Saturdays in 2022.

Galleon rides again: Readers of my newsletters may remember I was bemoaning the loss of winter cauliflower varieties from Canadian seed suppliers last year. If you want to grow overwintering cauliflower plants next season, I am happy to let you know that seeds of ‘Galleon’ (an excellent, very hardy variety) are now available through Salt Spring Seeds. These were grown this year by a small band of Salt Spring gardeners who grew out their Galleon plants for seed and pooled them to maintain genetic diversity. Some growers on Salt Spring have now planted larger areas of ‘Galleon’ for seed collection next summer so I hope we are on the way to keeping this variety from being lost. SS Seeds also lists ‘Purple Cape’, another excellent overwintering cauliflower.

November 22, 2021 11:18 AM