When to Vent Cold Frames

Reader Contribution by Rebecca Martin
article image

How should I monitor my garden cold frame on warm days to ensure I’m not frying my plants? Do I need to check the temperature every hour?

No, not every hour, but you’re right to err on the side of vigilance anytime the sun is out — even if the temperature isn’t particularly high.

During spring and fall, when temperatures range widely, check your weather report early in the morning. If the day will be sunny with temperatures above 50 degrees Fahrenheit, the cold frame’s internal temperature will rise too high for your plants, so you should crack the lids open to allow excess heat to escape. Close your units up at twilight if the forecast predicts nighttime temperatures below your plants’ cold-tolerance level.

Photo courtesy Cedar Cold Frames: Even when snow surrounds your cold frame, the plants inside may need a breath of fresh air.


Rebecca Martin is an Associate Editor at MOTHER EARTH NEWS magazine, where her beats include DIY and Green Transportation. She’s an avid cyclist and has never met a vegetable she didn’t like.

Need Help? Call 1-800-234-3368