Starting in September, gardeners in temperate climates need to be ready to protect certain vegetables against that first frost. You know, the one that happens early in the season even though the weatherman is announcing weeks of warm temperatures afterwards. And all it takes is a touch of frost to stop the production of your tomatoes, peppers, cucumbers, beans, etc. Many of these plants will continue to mature until late October or even November in some climates… if you can keep that first frost at bay. Here are a few things you could do:
- Turn on the lawn sprinkler so it sprays your vegetables overnight. First, tap water is necessarily above freezing, but also, even if the air is very cold, moving water will prevent frost from entering the plants’ tissues.
2. Cover your plants. Use whatever is at hand: old sheets, floating row cover, geotextile, plastic film, newspaper, cardboard boxes, etc. You can even prepare ahead of time by installing right away the stakes, poles or structures on which your “protective tents” will rest so they won’t crush your plants. Remember to remove the covering the following day when the frost is out of the air.
3. If you grow your veggies in pots, move them to a garage, a shed, or indoors for the night, then put them back out when it warms up the next day.
It’s mainly fruit-bearing vegetables that require frost protection. Root vegetables are safely underground where early frost can’t touch them and most leaf vegetables will tolerate a touch of frost. Some vegetables even taste better after they have been frosted: fall cabbage, kale, leeks, parsnips, Jerusalem artichokes, etc.
When Frost Persists
But there is a limit to protecting plants against frost. When the weatherman announces frost night after night, it is time to harvest any vegetables that can still be saved. Cucumbers, beans, squash, eggplants, and peppers are perfectly edible even when immature. Tomatoes that have turned pale green or are starting to turn red will generally continue to do so if you put them in the pantry (they’ll have a better flavor better if you let them ripen in the dark rather than the sun). As for tomatoes that are still fully green… well, there are different recipes for green tomatoes (ketchup, jam, fried green tomatoes, etc.), so you can use them too.
But keep your fingers cross: that first frost might still be a month away!