Many backyard gardeners start their plants indoors in late winter or early spring, before the weather is warm. But the best way to jump-start plants for spring gardening and also extend the growing season into winter is with a backyard greenhouse. Our design is a 1.8 m × 2.4 m (6 × 8 foot) structure, large enough to accommodate dozens of plants but compact enough to fit into the smallest garden. It’s also easy to build, requiring only basic carpentry skills and easy-to-use tools. You can finish it over a couple of weekends.
The cost of the materials to build our greenhouse was about R20 000. That’s higher than some preassembled greenhouses, but our materials are more reliable than any ‘snap together’ model; plus, this one is customisable. We include a potting bench, overhead plant hanger, and deck, but you can add or subtract features as needed. Whether you’re an expert gardener or a rookie, our greenhouse will expand your gardening potential and diversify the kinds of plants you can grow at home.
→ CUT THE TIMBER FRAME FOUNDATION
Start by crosscutting two pressure-treated 89×140 mm timbers to 2 440 mm long, and two others to 1 830 mm long. Mark both ends of all four timbers for a 44 mm-deep × 140 mm-wide half-lap joint. Set the depth of cut on your circular saw to 44 mm, and make a shoulder cut across the timber precisely 140 mm from each end of the four 89×140 mm boards. Then set the saw to its maximum depth of cut and make the cheek cut in from the end of the timber [1].
Flip the timber over and make another cheek cut into the opposite edge. To complete the half-lap joint, trim away the last bit of waste wood with a reciprocating saw or handsaw. Repeat to cut half-laps into both ends of all four 89×140 mm.
