Edmonton Frost Warning: What to Harvest, What to Cover, and What to Leave Alone
A frost warning is in effect and we've received a lot of phone calls and emails from people asking about what can stay outside and what needs to come in.
Here's our quick guide:
Apples: A light frost will not affect the apples and may even make them sweeter. Barring a severe September storm, leave your apples on the tree until they are ripe (mid- to late- September for most late bearing apples).
Beans and Peas: Will not tolerate frost. Harvest these guys and eat them up!
Beets, Carrots, Onions, Parsnips, Potatoes: Protected underground, these vegetables do fine in a light frost and their flavour will likely improve with the cold. That said, harvest them before the ground freezes.
Chard, Kale, and Cabbage: These plants should all survive a light frost. Cold temperatures will even intensify the colour and flavour of chard, and may sweeten cabbage.
Corn: Corn is frost sensitive. If your corn is ready, pick it now. If it is not yet ready to harvest, cross your fingers and hope for the best. A hard frost will reduce the shelf life of corn to 3 to 4 days.
Lettuce and Salad Greens: Cold will affect the look and texture of lettuce and salad greens, but they can survive a light frost. If you’d like, harvest the tops of the lettuce and see if they come back afterwards.
Strawberries: If they're ready: harvest them, if not: cover them. Frost can affect the texture of the berries.
Tomatoes and Peppers: Harvest any ripe tomatoes and all peppers. Unripe tomatoes are bit more complicated. If you’re feeling cautious and would rather not deal with any stress, harvest them all now—ripe or not.
If your tomatoes are in containers and you’re feeling daring (and if the forecast cooperates), you may be able to get away with moving and covering your tomatoes. Bring the tomato vines close to the house (preferably on the south side of the house) and cover them with some light fabric to protect them from the frost.
However, if the forecast dips below -2°C, the tomatoes will probably end up covered in frost anyways even with these precautions. Keep an eye on your local temperature, and harvest the unripe tomatoes if necessary. Green tomatoes can be ripened inside on sheets of newspaper.
Pumpkins, Squash, Zucchini, Cucumbers: Cucumbers, zucchini, and summer varieties of pumpkin and squash should be harvested now, wiped dry, and cured in a hot, dry room for a few days to improve shelf life.
Properly cured, they may store for a few weeks. Avoid storing these fruits on concrete or metal surfaces as it can cause them to rot.
Thin skinned cucumbers will not store as well and should be eaten within a few days.
Some pumpkins and squash are "winter varieties" and can store very well if properly cured. Harvest any mature “winter variety” gourds before a frost (they will have a nice tough skin when mature) and do your best to protect the immature ones by covering them with a sheet. Immature gourds will not ripen off the vine or once the vine has died, so protecting them and hoping for the best is the best strategy. Be careful not to crush the vines.
For protecting your plants, our best product recommendation is frost protection blankets. NuVue's Insulating Winter Blanket is great for long garden rows as it is already cut at 42 inches by 25 feet.
For square & rectangular gardens, use DeWitt's N-Sulate Frost Protection Blanket which is 12 feet by 10 feet.
You can also use Crop Cover Fabric to protect sensitive plants. While lighter weight, Crop Cover Fabric protects against insects, freezing rain, frost and snow damage, while allowing air and moisture to reach the crop.