Gardens Outdoor Fine Woodworking

Cold

Frame

Extend your growing season

with this warm environment

by Rob Wotzak

E

xperience has taught me that the simplest solution is often the best. I

wanted to spend more time using my new cold frame than building it,

so I designed a compact, easy-to-move, low-maintenance box with a

special feature: a hydraulic riser. This heat-sensitive opener regulates the tem-

perature in the cold frame so that I don’t have to check on my plants as often.

Cold frames are little solar greenhouses that provide a favorable environ-

ment for hardening off seedlings, growing cool-weather

crops, and protecting tender perennials. They don’t require

outside energy; instead, they collect and retain warmth

when the sun’s rays penetrate the clear-plastic, glass, or

fiberglass sash. The walls of the frame are most often con-

structed out of wood, but it’s not unusual to use concrete,

stone, or even straw bales. There is no standard-size cold

frame, so its dimensions will depend on the amount of

available space, how you plan to use the cold frame, and

the size of your sash material; 3 to 4 ft. is a convenient

space to reach across.

I used a 72-in.-long and 36-in.-wide sheet of acrylic for

my sash and clear 2x6 cedar for the structure. The cost of

cedar is justified by aesthetics; plus, the wood is rot re-

sistant, lightweight, and easy to work with. I attached the

2x6s to 2x2s in the corners, and the sash frame is made

out of 1x2s.

Because this simple design requires only a few different

lengths of wood, you might want to ask the folks at the

lumberyard to make all your cuts to size, which they will

often do for free or for a small fee. The only tricky cut to

make—and the only one they won’t make for you at the

lumberyard—is the one to create the triangle-shaped side

boards, which are made from one 33-in.-long 2x6 cut on

the diagonal.

Rob Wotzak is a carpenter and a web producer for FineHomebuilding

.com and GreenBuildingAdvisor.com.

Wood

For the base:

•   Four 31-^1 ⁄ 2 -in.-long 2x6s

•   Five 71-in.-long 2x6s

•   one 33-in.-long 2x6

•   two 9-^1 ⁄ 2 -in.-long 2x2s

•   two 15-in.-long 2x2s

For the lid:

•   three 72-in.-long 1x2s

•   three 34-^1 ⁄ 2 -in.-long 1x2s

•   three 33-in.-long 1x2s

What

you’ll need

GLAZING

ANd hArdWAre

•   one 72-in.-long

by 36-in.-wide

sheet of clear acrylic

•   three 3-in.-long

stainless-steel or brass

strap hinges

•   one solar-greenhouse

vent opener

•   twenty-four 1-^1 ⁄ 4 -in.-long

stainless-steel self-

tapping deck screws

•   Forty-six 3-in.-long

stainless-steel self-

tapping deck screws

•   Fourteen^3 ⁄ 4 -in.-long

stainless-steel pan-head

screws

gardEn pRojects

26 FINE woodworkINg

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