Frost in the forecast? A few practical checks can help protect your raised-bed crops. Learn when to cover, how to check soil moisture, and what to do the next morning.
Garden Frost Protection: Get Ready for a Chilly Night
There’s plenty to love about a cool-weather garden: fresh greens, crisp roots, and another reason to step outside. When frost enters the forecast, a little preparation can help protect what you’re growing.
Start with a look at your local forecast and a quick walk around your garden. These five steps will help you get ready before the temperature drops.
1. Know which plants need your attention
Take a quick look around your Garden Grid™ squares. Tender crops like tomatoes, peppers, and basil need more protection than established kale and spinach, which can tolerate light frost.
Give young transplants extra attention, even if they’re cool-season crops. Check both the overnight low and how long the cold will last—a brief frost is different from a night of freezing temperatures.
If a stronger freeze is coming, pick ready-to-eat produce from vulnerable plants before covering them. Enjoying what’s ready is part of the reward.
Still growing tomatoes or peppers? Protecting them through a brief cold snap can be worthwhile if warmer weather is returning. If cold weather is settling in, focus on harvesting usable fruit rather than expecting covers to keep warm-season crops producing.
Want to keep a favorite pepper plant for another season? Overwintering is about keeping the plant alive—not expecting winter harvests. Our eggplant overwintering guide also introduces the approach for peppers.
2. Cover the bed before the temperature drops
Image via NewOldStockPhotos
Cover your plants before sunset to help hold warmth from the soil around them. Have your frost cloth and clips or weights ready during the day so you’re not hunting for them after dark.
Use a piece of frost cloth large enough to cover the whole bed. Bring the edges down to the soil or secure them around the raised bed’s sides, closing gaps where wind can get underneath.
Use hoops or sturdy supports, such as GIM™ Tomato Cages, to keep the cover from weighing down delicate plants. Hold the edges in place with clips, boards, or weights.
No frost cloth? A supported bedsheet can work in a pinch for a brief, light frost. If you use plastic, keep it off the leaves and check the temperature underneath on sunny days.
Want a simple cover you can put together yourself? Watch GIM® Co-Founder Tom build a simple raised-bed greenhouse cover in about five minutes: See our quick DIY greenhouse guide.
3. Give your soil a head start on the cold
Moist soil absorbs and stores more daytime heat than dry soil, then releases that warmth overnight. A secured frost cover helps retain some of that heat around your plants.
Check a couple of inches below the surface in several Garden Grid™ squares. If the soil is dry, water thoroughly during the day, before freezing temperatures arrive. If it’s already evenly moist, you’re ready to cover.
A Garden Grid™ makes it simple to water across your entire growing space at once. Adjust your watering to the soil and weather rather than leaving a summer schedule unchanged.
Finish watering before freezing temperatures arrive, then cover the plants that need protection. The moist soil and cover work together to help hold warmth around your garden.
Get help with watering timing and frequency
Mulch helps insulate roots and soften soil-temperature swings. Spread it over the surrounding soil, leaving a small gap around stems and crowns to avoid trapping damp mulch against the plant’s base. Use a cover to protect the foliage above it.
4. Add a little warmth when needed
Old-fashioned incandescent holiday lights can do more than decorate. They produce heat that helps warm the air around your plants beneath a frost cover. An incandescent bulb in an outdoor-rated fixture can help, too. Use incandescent lights, not LEDs, which give off too little heat for this job.
Use outdoor-rated lights and cords with a GFCI-protected outlet, keep connections dry, and keep hot bulbs clear of plants, mulch, and the cover.
5. Check beneath the cover
Keep protecting your plants while the freeze lasts. Plastic covers can stay in place to hold warmth, but on sunny days, temperatures underneath can climb even when the outside air feels chilly. Check beneath the cover and open the sides if it’s getting too warm—a small thermometer makes this easy.
Remove temporary bedsheets once temperatures are safely above freezing so plants can get daylight. Breathable frost cloth can often stay on through a stretch of freezing weather.
Let frozen leaves thaw before handling them.
Your before-evening checklist
- Check the local overnight low and wind forecast.
- Identify tender crops and young plants that need protection.
- Pick ripe produce from vulnerable plants if a stronger freeze is coming.
- Water dry soil during the day; leave already-moist soil alone.
- Secure a suitable cover before sunset and check it again in the morning.
A chilly forecast is a reason to get ready—not a reason to stop enjoying your garden. Protect the plants that need it, keep picking what’s ready, and make the most of the growing weather ahead.
