It is too cold to start most cool-season annuals, and propagation by hardwood cuttings works better in a cold yet sheltered environment. Ditto for pots of springtime bulbs you are trying to force into early bloom and seeds that need to be stratified. However, with a little creativity, you can get such small, outdoor garden projects going this winter in spite of the weather.

The cold frame option

The secret isn't really a secret: A cold frame is the way to go for growing in the winter. It is a simple covering for developing plants, but if used properly, it can keep the killing winter winds and frosts off plants and can retain some daytime heat for long, cold winter nights.

The clear covering for a cold frame can be anything that lets the sun shine in such as polyethylene film, plastic panels, glass panes or even old storm windows. It comes down to what you have to spend or what you have tucked away in the garage.

The ideal location for a cold frame should be a spot that allows you to turn the open end toward the southern winter sun for maximum exposure to the warming rays. Also, if you put the northern back of the frame up against something (a building or even a mound of dirt), it will provide some protection against frigid North winds.

Getting started

Before you plop your miniature greenhouse down, prepare the soil it will cover. Fine, friable dirt that has been fertilized is the ticket. This allows you to start either seeds or plantlets in the frame. However, if you want to use the enclosure to play with plants in pots, well, at least you will have some nice, loose dirt to stick the containers in, which is not a bad idea since the pots can be set into the earth to provide even more insulation for the roots.

Lumber or hay

And just what should you use for walls? Boards seem to be the obvious choice, and amateur carpenters can have a field day on this project. But creativity can be the guide with two conditions: (1) Make the walls at least 2 feet high to give tall plants room; and (2) paint the walls on the inside white to reflect as much of the weak winter rays as possible to the sheltered plants.

Now if trying to figure out what to do with the boxy frame come summer is too perplexing, then a cold frame with disposable walls might be the way to go? Yes, there is such a thing.

Take four or more bales of hay and form them into a "U" shape facing south. The thick hay will offer insulation against the cold, and in the springtime, you can tear the "walls" apart and use them for garden mulch.

Making it work for you

The operation is simple. On sunny days when the temperature is 50 degrees or below, open the covering just a bit to let out excess heat. If it is sunny and above 50, open the frame completely to keep your plants from cooking. On cold, cloudy days and at night, though, keep it closed to conserve heat. If the sun is not shining, and it gets very cold (in the 20s or below), toss boards, blankets or whatever is handy on top of the clear covering to slow heat loss. Putting a thermometer in the box will go a long way in helping you to determine whether to open, close or cover.

You don't have to water your sheltered plants that often. A cold frame not only keeps heat in but it also retains moisture. Over-watering can lead to diseases and rot.

Get $150+ in coupons in every Sunday N&O. Click here for convenient home delivery.