Build a cold frame

It is a warm and sunny weekend in Seattle - ideal for outdoor spring cleaning and pea planting - but alas, I am confined to the chesterfield with the flu.

It’s not all bad though - I’ve been able to prepare a long list of projects for Urban Land Army’s Head Scavenger, Baker, and Master Builder, and he’s already tackling the most pressing and exciting one: the cold frame.

A cold frame is essentially a mini-greenhouse - a box with a glass lid - where you can grow burly little seedlings like lettuce, spinach, beets, parsley, and other hardy greens. Starting them outside in a cold frame lets you get a jump on the season, and it frees up space indoors for growing the more sensitive, heat-loving crops, like tomatoes, peppers, and basil. You can also use the cold frame to “harden off” (toughen up, weather-proof) these plants when they move outdoors in late-spring.

In researching building plans for cold frames, I came across a detail-oriented Canadian who provides a materials list, photos, and step-by-step instructions for building this solid and most excellent cold frame.

Note that building this particular cold frame is not for the faint of heart - you will require a circular saw and at least a rudimentary understanding of beveling - but you can simplify the design and take what you need from it. The basic principles - taller at the back than at the front, a wooden box with a hinged glass lid, are all there.

Prefer old-fashioned bricks and mortar or no-nonsense concrete blocks? These would work as a base too: just stack them up and add a glass or plexiglass top that is secured, weighted down, and easily removable in some way, shape, or form.

As for us, Head Scavenger has accumulated a good deal of scrap wood and old windows, so a quick trip to the back of the garage and we were well on our way to having a cold frame that means business.

The mock-up:

I will report back next weekend when the cold frame will hopefully be primed and painted, and ready to house the first seedlings of spring!