While it’s possible to plant on slopes without using raised beds, water run-off means the soil and plants dry out quickly. Terrace garden beds are the perfect solution and it means flowers and vegetables can be grown in a space that might otherwise be wasted.
The contours of your garden will guide your design, but when starting out, restrict your terraces to a manageable size. Large terraces need proper drainage and extra reinforcement; the pressure of water-logged soil behind a wall can be huge and cause large or improperly constructed walls to collapse. A series of small beds is easier to construct and a safer option.
Use sturdy material (plywood won’t cut it) and make sure your beds are securely anchored in place.
2 x lengths 2.2m x 200mm x 50mm rough-sawn tanalised pine
4 x sides 500mm x 200mm x 50mm rough-sawn tanalised pine
6 x wooden pegs (stakes) 600mm x 45mm x 35mm
100mm x 4mm flathead galvanised nails
75mm x 3.15mm flathead galvanised nails
Small stakes for marking out beds
Spade; Tape measure; Level; Electric drill; Hammer; Sledge hammer
Measure and mark out the size of your first bed using small stakes. Ours is 2.2m long and 550mm wide. Allow another (at least) 250mm for a small walkway in between beds.
Start building your beds. Dig a trench for your first tier, 200mm deep at the back and 80mm wide (includes 250mm for the walkway). Make sure the base of your terrace is level.
Start digging your next tier, 800mm out from the bottom edge of your first tier.
Place the 2.2m lengths on each tier, 500mm from the back walls. Check that each terrace is level.
Position the side pieces in place. Drill three pilot holes through each bed end, then nail in place with the 100mm galvanised nails.
Drive pegs into soil with sledge hammer. Position two of the pegs 30mm in from each end, and one in the centre, driving each peg 20mm below the top of the bed. Drill two pilot holes into each peg and secure with 75mm nails. You can now fill your bed with soil.