Garden & Greenhouse


Cold Frames and Cloches

Posted January 15th, 2016 by Clair Schwan in ,

Cold frames are simple devices that are versatile and can help you all year long. I know that we usually think about these things in terms of getting our seedlings started in the spring, but they also help promote protection in the summer, extend the season into the fall and can allow us to even harvest vegetables in the winter. And, they’re great seed starters any time of the year.

A key element of my plans for greater self-sufficiency includes being able to harvest long after the summer season is over. If you build a framed device like these, you’ll be able to do much the same. Wouldn’t it be nice to forget about the higher cost of produce in the winter and simply enjoy something fresh from your garden? I think so.

I know it seems unlikely, but a cloche (pronounced clo-shh), row covers and cold frames can be a year-round helper to protect against frost, hail, storms, critters, bitter cold and high winds. It’s relatively easy to create your own, and simple cloches cost almost nothing to construct. Let’s look at the principles and advantages of these devices so we’ll understand how best to use them.

They Offer Physical Protection

Whether you have tender young plants, healthy growing plants, or a crop that’s getting ready to harvest, they could all use a little protection from the elements. Simple cloches or cold frames can help you in this regard.

Here in Wyoming, we have high winds that will bend plants over and dry them out. We also have more occurrences of hail each year than anywhere else in the United States. Providing plants with physical protection is a must if we’re going to keep them healthy and producing food for us. When I lived in Michigan, we would have rain that lasted for days on end, sometimes a good hard rain. This type of precipitation can knock plants to the ground and wash soil away from surface roots. Protection for the plants is helpful to minimize the effects of such weather.

Only the smallest and most persistent of critters will get into your cold frames and cloches to nibble away on your plants. I have trouble with mice, but a tightly closed cloche helps keep them out. A framed protective structure can foil rabbits and birds as well. Having problems keeping your dog out of your garden? If it’s contained within a protective frame, you have the problem nearly solved. There is nothing that says you can open up the top of your protective frame and let the sun shine in. A top of poultry netting can discourage most animals from traipsing through your vegetables.

Moisture is Retained

In climates where warmth and wind help dry out the soil, frames and cloches can help retain moisture. This is especially important when first planting seeds and trying to grow seedlings. There is little danger of overheating the soil and killing young plants by trapping in heat from the sun, so sealing things up with framed-in protection helps warm the soil and keep moisture right where it’s needed to sprout the seeds.

For mature vegetable plants, it’s probably not a good idea to have a humid environment, as it tends to promote diseases, but it’s a good thing for small seedlings. Just be sure to wean the seedlings off the humid environment a little at a time. If you try to take them out of the moist environment and into a relatively dry one, they’ll be shocked and could possibly die. Let them get used to the change in environment a little at a time, perhaps over three to four days. When warmer weather comes, you’ll want to make certain the cover is vented to keep plants from wilting under the higher temperatures that can be generated in these miniature greenhouses.

Miniature Greenhouse

The overall advantage of cloches or cold frames is that you’re creating a type of greenhouse for your plants or seedlings. It’s essentially a miniature greenhouse that is manually operated. That means it offers the same type of protection, moisture retention and multiplication of the sun’s efforts as would occur in a larger greenhouse, only in a much smaller structure. Keep in mind that cloches and similar devices will heat up and cool down very quickly, within minutes, so regulation of the inside temperature will be tricky. And, it most likely will be a manual activity.

Having these miniature greenhouses will allow you to grow earlier than normal, later than normal, and with cold hardy vegetables, you’ll be able to harvest in the winter as well…long after your summer vegetables are on the compost pile.

A Clear Thermal Blanket

Cloches and cold frames offer a type of clear thermal blanket for a small grouping of plants or a single plant. They help trap in the warmth of the sun which heats up the soil and air inside. The blanket effect isn’t quite what one might expect from a blanket because we’re only talking about a single layer of plastic, so its insulating effects are from trapping “dead” air inside. Air that isn’t moving can’t transfer heat as well, so that’s how heat is retained.

To boost the thermal blanket effect after the sun goes down, cover your cloches or cold frames with old sleeping blankets, sheets, towels, old blankets or other material that offers some type of insulation. It will slow down the release of warmth as well as the intrusion of colder air.

Drawbacks of Cold Frames and Cloches

It’s only fair to list the potential drawbacks of cold frames and cloches as there are some to keep in mind. Here they are with brief explanations:

Limited Growing Space

Usually cold frames and cloches are small and limit the number and size of plants you can grow. You simply can’t have a large garden inside of these structures.

Difficult to Regulate Internal Temperature

With fast heat up from the sun and quick cool down from opening the enclosure, cold frames and cloches aren’t going to maintain a constant temperature unless you have constant weather conditions and you carefully adjust openings in the enclosure to bleed off excess heat.

Risk of Plant Wilt

If you seal up your plants to endure a chilly overcast day and then the sun comes out, you’ll have “cooked” plants within an hour or so unless you recognize the sun breaking through and take action to make adjustments to vent excess heat.

Some Inconvenience

Whether you’re trying to work inside one of these structures or work around them in the garden, they are a bit inconvenient.

Great Little Garden Helpers

So, if you’re inclined to get a head start, extend the season, or garden “out of season,” cloches and cold frames are probably just what you’ll want to employ. They are quick, easy to make and allow you to get a head start on the season. Best of all, they don’t have to be expensive, so your vegetable gardening interests will be fully supported by these little enclosures at a small price tag. Whether you use wood, PVC, wood and steel or just make a plastic tepee over your plants, you’ll enjoy the advantages that cold frames and cloches afford you.

Clair Schwan is an avid vegetable gardener who considers his gardens to be important assets. To him, vegetables in the garden are a bit like money in the bank. It’s all part of his self-reliant lifestyle. See his adventures in gardening and more at

Want more information? Read these articles:

Going Green with Your Greenhouse

Have a Plan Before Purchasing a Greenhouse

Hot Bed – A Simple Greenhouse

How to Build a Plastic Greenhouse

Winter Greenhouse Gardening Tips

Subscribe to Garden & Greenhouse Magazine

Subscribe to Garden & Greenhouse Email Newsletter