Extend your harvest and protect your plants all year long!
Few tools in the gardener's shed are as humble yet heroic as the cold frame. Like a miniature greenhouse, these low-tech contraptions create a microclimate that can squeeze out a few more precious weeks, or even months, of garden benefits!
Whether you're protecting crops from a surprise spring freeze, pushing your fall vegetable garden a little longer, or giving your seedlings a place to harden off before they brave the great outdoors, a cold frame just might be your new best friend in the garden.
By capturing solar warmth and sheltering tender plants, cold frames shield crops from frost, wind, and sudden temperature drops. Gardeners have used these passive solar protectors for centuries, from medieval stone-walled gardens to today's raised bed wonders. Also known as a sun box, propagation frame, cloche, or grow box, these are affordable and adaptable! A cold frame helps you protect prize plants, extend harvests, and get a jump on the growing season. All with the help of Ma Nature herself.
- Types Of Cold Frames
- How To Use A Cold Frame All Year Long
- Cold Frame Tips & Tricks
- Extend Your Growing Season With Cold Frames!
What Is A Cold Frame?
A cold frame is a simple, ground-level enclosure with a transparent lid that traps solar heat. This passive heating creates a warmer environment than the surrounding garden, allowing you to extend your growing season or protect vulnerable plants from sudden weather swings. Similar to adding plastic row covers to your garden beds, a cold frame is a more permanent garden addition.
Typically constructed from wood or metal with a clear lid made of glass, acrylic, or polycarbonate, a cold frame can be as elegant or as makeshift as your creativity allows. Some folks even build them using a stack of hay bales with a reclaimed window on top. You can repurpose old materials or buy a pre-fab option, the result is the same: a pocket of warmth to protect your plants.
Banking soil along the outside walls or partially burying your cold frame helps retain heat. For extra heat retention, try painting the interior black to absorb sunlight during the day and slowly radiate it back overnight, just like dark rock walls in traditional European gardens.
Types Of Cold Frames
There's no one-size-fits-all when it comes to cold frames. Choose or build a version that best suits your garden goals:
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Traditional Wooden Cold Frames: Built with wood and a hinged glass or plastic lid, these durable designs blend into most gardens and are easily customized.
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Metal-Framed Cold Frames: Lightweight, rust-resistant, and long-lasting, they're ideal for mobility and ease of use.
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Pop-Up Cold Frames: Portable and compact, these are perfect for small-space gardeners or quick season extension.
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Raised Bed Cold Frames: Combine a raised bed and cold frame for dual-season power, especially helpful in colder regions.
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Electric Cold Frames: With built-in heating elements, these let you garden year-round, even growing warm-season crops through winter.
- Hay Bales & Reclaimed Windows: When you need a cold frame in a pinch, stack hay bales into a square and top with a salvaged window or clear sheet.
How To Use A Cold Frame All Year Long
Perfect for starting your first batch of seedlings, nurturing tender perennials, or harvesting fresh greens in the snow! Cold frames are a must-have for any garden enthusiast!
Cold frames aren't just a springtime tool either. They can serve many purposes across the seasons, expanding your gardening potential with every use.
Spring
- Harden Off Seedlings: Transition your indoor seedlings to the garden using a cold frame. Gradually introduce indoor seedlings to the elements by sheltering them in a cold frame for part of the day. Start by placing them inside the closed cold frame for a few hours a day, gradually increasing light and air exposure.
- Jumpstart the Season: Start early crops by planting cool-weather vegetable garden crops like lettuce, spinach, kale, and radishes weeks before the last frost. The cold frame will protect them from chilly nights and give you a head start on the season.
- Warm the Soil: Heat the soil faster to sow seeds earlier and get a jump start on the growing season.
- Guard Against Cold Snaps: Protect plants and seedlings from unexpected frosts and dips in temperature.
Summer
- Shade Young Plants: Use a cold frame to reduce wind stress or shield transplants from harsh afternoon sun.
- Protect Delicate Plants: Use your cold frame to shield young transplants from intense sun or strong winds.
- Extend Harvests: Late-season crops like Bush Beans or Cucumbers can thrive in the controlled environment of a cold frame.
- Quarantine: Place new plants in a protected form of isolation until you can be sure they are pest-free. Or use a cold frame to isolate a plant during treatment of an outbreak to keep the pests from spreading.
Fall
- Extend the Growing Season: As temperatures drop, use your cold frame to grow hardy greens, carrots, and beets well into late autumn.
- Save Tender Plants: Move Herbs or smaller potted plants into a cold frame to protect them from early frosts.
Winter
- Winter Gardening: Cold frames are perfect for cool-season vegetables, hardy greens like kale, chard, and spinach, keeping them fresh even in snowy conditions. Cruciferous vegetables can be kept growing longer here, too!
- Storage: Use your cold frame as a temporary shelter to store pots or trays of dormant plants. Keep seeds where they won't freeze but remain cold. Or just use your cold frame to keep tools and supplies clean, dry, and rust-free.
- Root Cellar: Store dormant bulbs, edible tubers, root vegetables, and other vegetables between layers of straw, clean mulch, or sand in your cold frame. You can also cover plots of root crops while they're still growing in the ground with a portable cold frame to extend your harvest.
Cold Frame Tips & Tricks
- Placement: Position your cold frame in a sunny spot with southern exposure for maximum warmth.
- Ventilation: Open the lid on sunny days to prevent overheating and allow airflow.
- Insulation: Add extra protection in winter by lining the sides with straw or bubble wrap.
- Maintenance: Keep the panels clean to allow maximum sunlight to reach your plants.
- Moisture Control: Avoid overwatering or letting condensation build up. Too much can encourage mildew and disease. Watch for soggy, wet foliage and open the lid to air out your crops when temperatures are safe.
- Use the Finger Test: Before watering new plants, always check the soil moisture by using the Finger Test.
- Rodent & Pest Protection: Secure the base with wire mesh or hardware cloth to deter nibblers and diggers like rabbits or voles.
- Compost Pairing: Place your cold frame near or over an active compost pile. The heat from decomposition can add warmth and boost growth.
Extend Your Growing Season With Cold Frames!
Cold frames are a game-changer for gardeners! Offering endless possibilities to grow more plants, extend your harvest, and protect your garden from unpredictable weather. From salvaging a late harvest to giving your spring garden a head start, cold frames offer a simple, time-tested solution to stretch your garden's productivity. These versatile garden allies don't just extend your seasons, they expand your possibilities!
It doesn't matter if you're building one from scratch or selecting a ready-made version; the cold frame's blend of old-world wisdom and modern utility is sure to enrich your edible landscape! They're an affordable and effective way to make the most of every growing season while giving your plants the best chance to thrive.
Nature Hills Nursery has plenty of plants to help you fill your new cold frame! We're sure you'll find the perfect fit for your gardening needs. Bring your garden to life year-round with this simple yet powerful tool!
Happy Planting!
