From Linda Gilkeson:
Well, here it is: The first really wintery cold weather is forecast to arrive this coming week. It may get truly nasty after Tuesday with snow and very low overnight temperatures forecast by Thursday. SO right now, this weekend, finish all mulching and supplement any mulches that might have packed down in the rain. And now you can layer enough mulch on top of beds of carrots, beets and other root crops to completely cover over the tops. If needed, lay light boards, sections of stucco wire or chicken wire on top to hold leaves or straw in place. The thick mulch essentially turns the root crop bed into a living root cellar. Snow is predicted too, therefore check that your large plants, such as winter cauliflower, broccoli, Brussels sprouts, are well staked up so they won’t get pulled over or broken by the weight of wet snow.
While you are in the garden, cover lettuce, Swiss chard, salad greens, spinach, with tunnels, plastic or whatever you are using for winter protection this year. At the moment, the forecast lows are low enough for some areas (-5oC/23oF) that leafy greens would be damaged if they aren’t covered. Kale, parsley, and corn salad are not at risk at these temperatures, though. I have a stockpile of tarps and plastic sheeting (and heavy rocks to hold them down) that I deploy for cold snaps as needed, but am seriously considering installing more permanent tunnels or movable coldframes to protect leafy greens in the garden. Despite warmer average winters, the lowest low temperatures in the winter in this region have been decreasing over the last 3 decades. It is harder to get leafy greens through the winter in good shape without covers than it used to be. If you already have sturdy tunnels for such crops, you are all set, but don’t forget to mulch inside the tunnel too.
If you are growing in an unheated greenhouse, remember that overnight temperatures will get nearly as cold as outdoors. If temperatures go as low as currently forecast, cover greens in the greenhouse with tarps overnight. While snowfall insulates outdoor plants from cold, plants in unheated greenhouses won’t have the benefit of snow.
It is another La Nina winter (an unprecedented third year in a row!) so we can expect another stormy, cold winter. I won’t send out a warning every time, but be watching the weather for two temperature thresholds: At around -5oC (23oF) leafy greens mentioned above should be covered. At around -9 (16oF) other above-ground crops (winter broccoli, cauliflower, cabbage, leeks, kale) should be covered. There are differences in hardiness between cultivars, with some OK at even lower temperatures, but to be safe, I go by these thresholds. Gardens at higher elevations or in cold valleys often get colder than regional forecasts predict so err on the side of caution. Root crops buried under mulch, as described above, will be fine at these lows, but double check that roots that bulge above the soil, such a celeriac and cylindrical beets that really stick up above the soil, are well protected by mulch.
I know there are a few of you out there that still haven’t planted your garlic—so do that, right now! Plant where no garlic or other onion crops have been growing in the last 4 years. The soil is too wet to handle so you won’t be able to mix compost or other amendments into the soil. Just plant the cloves anyway and worry about feeding the soil next spring. Don’t forget to spread mulch on the planted bed. Next March, pull back the mulch to bare the soil and spread compost as a top-dressing to feed the bulbs. If necessary (for new gardens or poor soil), you could spread a complete organic fertilizer on the soil first and then spread compost on top of that. Ideally, replace the mulch on top of the compost to continue to kill weeds and protect the soil from heavy rain.
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.