Cold snap forecast.
Right now the forecast after Sunday shows a period of colder weather than we have had so far this winter. Forecasts are for overnight lows of -5 to -8C (18-23F) for much of the south coastal region. It could be colder than that in gardens in frost pockets and low-lying inland areas. If you have been lulled by the mostly warmer-than-normal winter so far, it is time to check up on your frost protection. As I was checking my garden last evening I found that I need to considerably beef up mulch that has become flattened around leeks, celeriac, cabbage and some other plants. The forecast does include some snow, which is a good thing for gardens because it adds a layer of insulation over everything.
Late cold weather is always harder on fruit trees and other plants once they have started to grow than it is when plants are fully dormant, but don’t worry about garlic and spring bulbs that have poked up shoots. They are quite hardy and likely to be fine. Fruit tree buds on the earliest blooming trees with swollen buds might be damaged, but later blooming trees should be fine—it depends on how cold and how long the cold snap persists.
To avoid leaf damage, you might want to harvest lettuce, spinach, chard, leeks and other above ground crops before the cold snap. Then throw a sheet of plastic or a tarp over the leafy greens beds. Unless it gets substantially colder than forecast, winter broccoli and cauliflower, kales, cabbage will be fine, but if it goes down to -10C (14F) or below in your garden, then these plants will be less damaged if you can throw a tarp over them for a few days.
Which reminds me, if you have finished picking your Brussels sprouts don’t take out the plants (even if they hardly have any leaves left at this point). They usually produce a whole other crop of sweet, tender shoots from each places along the stem where the sprouts came off. If you didn’t get nice round sprouts to form this year, you won’t get them in the spring, but the crop of side shoots all along the stem does provide a worthwhile crop.