Creating a Small Herb Spiral for a Sunny Corner

Why a herb spiral works in a sunny corner

A herb spiral packs many growing conditions into a footprint the size of a dining table. A low wall of stones or bricks coils upwards, creating a raised bed that rises from ground level to around 60–80cm at the centre. This gives free drainage at the top and moisture retention at the bottom. In a sunny corner, the spiral makes a perfect microclimate for Mediterranean herbs that hate wet British winters. It is cheap to build from reclaimed materials, beautiful, and highly productive.

Choosing the right spot and materials

Pick a corner with at least six hours of sun a day, ideally south or west facing, and shelter from strong winds. Keep it near the kitchen for easy picking. Aim for a finished diameter of 1.2–1.5 metres and a height of 60–80cm. Gather:

• Reclaimed bricks, stones, or broken slabs — 30–50 pieces
• Rubble for the core
• Loam-based compost, well-rotted garden compost, and horticultural grit
• Blood, fish and bone or rock dust
• String and a peg for marking the circle

Bricks stack neatly; stones look rustic. Avoid chemically treated wood or creosote.

Building the spiral, step by step

Mark a circle with string and peg. Loosen the soil underneath. Start at the outer edge, laying a course of bricks or stones around the circle with a gap for the spiral path, about 30–40cm wide. Coil inwards, raising the wall gradually so the outer end sits at ground level and the centre is highest. Build two or three courses at the outside, increasing to five or six at the top. Fill the path with compost as you go, so the wall has something to hold back. Tamp gently. At the centre, leave a small flat area for a thirsty herb. If wobbly, push small stones into gaps or use clay soil as mortar. A well-built spiral stands for years without cement.

Filling with gritty compost for free drainage

Sharp drainage is key. Mix two parts loam-based compost, one part horticultural grit, and one part well-rotted leaf mould or garden compost. For the top third, add an extra handful of grit per bucket. For the bottom third, use a richer mix with more compost and a little garden soil. Avoid peat. Add blood, fish and bone at planting time. Fill to 2–3cm below the wall top, leaving a lip to hold water. Water gently and let it settle.

Planting: Mediterranean herbs at the top, moisture lovers below

The top is hottest, driest, and best drained. Plant rosemary, thyme, oregano, sage, marjoram, and winter savory there. Space them 20–30cm apart. The middle slopes suit parsley, chervil, coriander, and basil in summer — wait until late May for basil. The bottom collects moisture, so plant mint, chives, lemon balm, and watercress. Keep mint in a sunken pot to control it. Plant in spring or early autumn when soil is warm and moist. Nasturtium and borage also thrive at the base.

Keeping your spiral productive through the year

Water the top daily in summer; the base needs less, so check a finger's depth down. Mulch with gravel or compost to slow evaporation. Harvest regularly, never taking more than a third of a plant at once. Trim rosemary, thyme, and oregano after flowering to stop them going woody. In winter, protect rosemary and bay with fleece or a straw mulch. Top up with fresh gritty compost each spring, and divide mint every couple of years. Built from waste materials, fed with homemade compost, and harvested fresh from a sunny corner, a herb spiral earns its place many times over.