Cold Frames

Buying coldframes online

Cold frames protect plants from frost and wind

It's important to protect your plants and seedlings from the cold winter and spring frosts; a good cold frame can help you do exactly that and relieve space in your greenhouse! They can be used to house bonsai and tender ornamentals over winter and in the spring can be used as a half way house to harden off plants raised in the home or greenhouse.

To help ensure you buy the right cold frame for your garden we explain the main considerations and review some of the websites where you can buy cold frames online.

Choosing the right size
Choosing the right material
Sliding or hinged 'lights'?
Other considerations
Alternatives to cold frames
Where to buy cold frames
Top products

Choosing which cold frame to buy - size

The first and main consideration when buying a garden cold frame is its size so here are the questions you should be asking yourself when choosing the right cold frame for you:

Does the cold frame fit into the area you have available?

This sounds obvious, but remember you will also need space around the cold frame to work, kneel down and move around it. “Lights” that slide open may also need extra space at the rear or sides of your cold frame so think about the things you'll do as you use your cold frame.

Will you be able to reach all corners of the cold frame?

If the back of your cold frame is against a wall or access to the sides is restricted consider where you will have access. You may need to reach the very back corners from the front of the cold frame. Most of the cold frames we've found to buy online are around 60cm (2') from the front to the back but some are over a metre (3'3”).

Will your cold frame be able to house your plants?

Remember to ensure that your plants won't grow too tall for the cold frame. Again, most are an average height of 35cm (1'1”) but there are taller and shorter ones available. Remember also that a cold house is usually taller at the back than at the front.

Choosing which cold frame to buy - materials

The transparent roof (and often sides) of cold frames are made from glass or plastic. Horticultural glass retains heat better than most plastics but twin-walled polycarbonate offers improved insulation over other single-walled plastics and is used on most popular cold frames.

Glass cold frames tend to be more expensive than plastic ones so if you want a bargain bear that in mind. If you have pets or children in the garden you may also decide to choose a plastic cold frame which won't be shattered by stray footballs. Glass will also be heavier than plastic equivalents; heavier cold frames will be more difficult to move but they will also be more resilient against strong winds. The material used to construct the frame will have the largest effect on the weight of your cold frame.

Wooden cold frames provide good insulation.

The most popular type of cold frame has glass or clear plastics sides. This glass-to-ground design lets more sunlight in during the day and often has a metal frame.

Aluminium cold frames are relatively cheap and lightweight. While cold frames with Aluminium walls offer less insulation than a wooden equivalent they have the benefit of being easily moved around your garden throughout the year.

Wooden cold frames are sturdier and offer better insulation than metal frames. Hardwoods like oak are more durable than other timbers but are also more expensive. If you are buying a wooden cold frame look for the letters 'FSC' (Forest Stewardship Council) in the product name to ensure the wood is from a sustainable and responsibly managed source. Both Crocus and Greenfingers offer FSC certified oak cold frames.

Choosing which cold frame to buy - “light” design

Cold frames have one or more transparent lids, called ”lights”. The “lights” are normally hinged or slide open to provide ventilation for the cold frame and allow easy access for you.

Sliding lights will need extra clearance around the cold frame to allow opening. The benefit of the sliding design is that they're less susceptible to strong winds than hinged lights which are propped open. The down side is they offer less protection from rain as there's nothing covering the cold frame when they're open.

A glass-to-floor cold frame with hinged 'light'.

Hinged lights provide better protection from rain as even when they're propped open, they are still above the cold frame, sheltering it. They are more vulnerable to strong winds than sliding lights but are the more popular design.

Some cold frames have lights on both sides, like wings, making it easy to reach all areas of the cold frame. If you choose this design, ensure you've enough space to get to both sides.

Other considerations when buying a cold frame

Some cold frames have a 'double decker' design that will house two layers of plants, great if space is an issue.

The insulation your cold frame provides will determine what plants you can store in your climate. Don't forget that you can add insulation yourself on particularly cold nights using whatever you have to hand; horticultural fleece, bubble wrap and old carpets can all be secured around a cold frame as additional insulation– just ensure they're removed during the day to allow light in.

Alternatives to cold frames

There are several alternative ways to protect you plants from the elements. Buying a greenhouse will provide you with more space for plants but is considerably more expensive and requires a lot more space. Fleece is a cheap alternative and will protect plants from the frost but doesn't protect as well against wind.

We have guides on buying cloches and buying mini greenhouses, both of which come at similar prices and offer very similar benefits to cold frames.

Cloches are suited to protecting plants that are already planted out (e.g. in you veg garden) and mini greenhouses protect potted plants the same as cold frames.

Where to buy cold frames

Websites selling cold frames online
Merchant	What we think
	Crocus offer a choice of materials and include a Brittania cold frame. Make sure they deliver to your area using their map and postcode selector to check your address.
	Greenfingers stock a range of cold frames, including Gardman cold frames and FSC certified wooden cold frames.
	Harrod Horticultural have a more limited range but stock items we haven't found elsewhere. They have received good feedback from our members and offer some nice alternatives to cold frames such as cloches.