How to Make Curves With Plastic Edging

Sketch your existing landscape on graph paper, keeping measurements in scale to buildings, fencing and plants. Add your potential curved garden bed. Large curves draw the eye into the garden and are easier to maintain; small curves appear artificial. Your sketch doesn't need to be perfect; aim for artistry over precision.

Paint the curves directly onto the ground according to your sketch. Study the potential curves from many angles, looking for blocked views or awkward areas, and adjust the curves as necessary.

Use stakes and twine if you have trouble making a semicircular curve. Hammer a stake into the center of the potential bed. Loosely tie twine to the stake, extend the twine and allow it to keep you anchored as you rotate around the stake. Mark the bed edges with spray paint as you move. For wider curves or ovals, loop a large circle of twine around two stakes. Stretch the loop to the bed's edge, forming a triangle with the twine, and hold the taut loop firmly as you move. Mark the curve with spray paint, again allowing the twine to anchor you. The wider the spacing between the stakes, the longer the curve.

Dig a vertical trench along the painted line with the flat spade, then dig a trench angled from the garden bed to the bottom of the vertical trench. Make sure the trench's depth is equal to the edging's depth. The vertical side supports your edging, while the angled side allows you room to install the stakes. Avoid rounded shovels or spades; the curved back creates a scalloped trench.

Set the edging into the trench, making sure the rounded top of the edging is flush with the ground. If the top remains above ground, winter frosts push the edging up. The exposed lip becomes an eyesore as well as a tripping hazard.

Hammer the spikes into the flat section of the edging, anchoring them into the soil behind the edging. Use eight to 10 spikes for every 20 feet of curve. Backfill and firm the soil.