Cold Frame Kit
A cold frame is rather like a spare bedroom for the garden. There are times when it seems to be in constant use with a stream of short-term visitors, at other times it’s residents take root and occupy it for several weeks at a stretch, after which it’s left empty for a while, while you both recover!
It is one of those universal truths that no matter how large your greenhouse, there are certain times of year when you wish it was larger. A cold frame is an inexpensive way of stretching its capacity. So, if you find yourself pondering about how you can possibly squeeze a few more plants into the greenhouse, onto the windowsills of your house, or anywhere else (I know someone who makes temporary use of her campervan), then it may be time to get yourself a cold frame.
Positioning a Cold Frame
Ideally, it should be positioned in a south-facing spot, close to the greenhouse – if you have one. My cold frame wandered around a bit as I tried different places, but it is now where it should have been in the first place directly opposite the greenhouse door against a south-facing fence. I can now move young plants effortlessly from greenhouse to cold frame and then out into the garden. I had been reluctant to give up this prime bit of growing space until I hit upon the ideal solution – come the end of May when all the plants are ready for planting out, I simply remove the lids and turn it back into a bed where I grow salads which will be harvested before I need the cold frame to sow cool-weather crops in the autumn. Although it is not essential to position your cold frame on soil, it does mean that you can sow or plant direct during the summer. Alternatively there will be space for a couple of grow bags in the cold frame and you can plant into them.
It is also the perfect place to overwinter sweet peas and other hardy annuals that are autumn sown – start them off in the greenhouse in autumn, then pot them on and move them to the cold frame. Except in the coldest or windiest weather, it is important to keep it ventilated to avoid plants getting clammy and then rotting. Look for a frame that has at least two stops to allow the lids to be either fully or slightly open.
Come the spring your plants can be hardened off. Do this by fully opening the cold frame during the day and closing it in the evening for about a week. They can then be stood outdoors until you are ready to plant them out. Although they are hardy plants, too much of a contrast in temperature too quickly can shock them and slow growth.
At this point it is a good idea to give the frame a thorough clean to get rid of any overwintering bugs and give the glazing a polish to allow maximum light to penentrate. From now, right through spring and on into early summer your cold frame will really earn its keep as it becomes the halfway house for all those lovely seedlings you have raised in the greenhouse, on your windowsills – or possibly in your campervan.