How to build a herb spiral

Inspired by a popular YouTube gardening guide. This walk-through draws on the video "DIY Herb Spiral: Grow More Herbs in Less Space!", which shows the full build from marking out the ground to planting. Good for getting a sense of scale and how the spiral shape is constructed before you start moving bricks.

1. Choose the right spot

A herb spiral wants as much sun as possible - a minimum of six hours of direct sunshine a day in summer. That usually means somewhere open to the south or south-west. Near the kitchen door is ideal: you want the herbs close enough to nip out and grab a handful while cooking.

Avoid spots directly under large trees where the soil will be dry and shaded. A herb spiral on a north-facing wall is a waste of effort.

2. Mark out the footprint

Most herb spirals are between 1.5 m and 2 m in diameter at the base - big enough to have distinct zones, small enough to reach the centre without kneeling in the beds. Use a cane and a piece of string to mark a circle; scratch the circumference into the soil with a trowel.

The spiral winds upward from the outer edge to a peak roughly at the centre. The finished height at the top is usually between 60 cm and 90 cm. Higher than that and it gets difficult to plant and maintain.

3. Lay the foundation layer

Dig out the turf and topsoil to a spade's depth across the whole footprint. Lay a base of rubble, broken bricks, or coarse gravel in the centre - this helps drainage and gives the structure something to sit on. For a feature that will last, it's worth laying the first course of bricks or stones dry on a bed of sharp sand rather than directly on loose soil.

You don't need mortar for a small herb spiral built to last a few years. Dry-laid stone or brick is perfectly stable if the courses are level and the structure is fairly low.

4. Build the spiral up in layers

Start the wall at the outer edge of the circle and wind inward and upward as you go. Think of it as a ramp spiralling up to the centre. Each course should overlap the joints below it - the same principle as any brickwork - so the structure doesn't have a continuous vertical crack that will let it collapse.

Step back regularly to check the height is consistent around the spiral and the courses are level. Minor adjustments are easy to make at the lower courses; once you're two or three layers up, re-levelling is messy. A gentle taper - wider at the base, narrower at the top - adds stability without much extra effort.

5. Fill as you build - different mixes for different zones

The clever part of a herb spiral is using different growing media in different zones. The top of the spiral, where drainage is fast and conditions are drier, suits Mediterranean herbs. Use a gritty, free-draining mix: roughly one part topsoil, one part sharp grit, one part horticultural sand. No added compost needed here.

The middle zone gets a more general purpose mix - topsoil and multipurpose compost, roughly 50:50. The base of the spiral, particularly the outer, shadier sections, can hold more moisture and suits herbs like mint, chives, and parsley. Standard good garden soil works fine there.

Fill each zone as you build that section of wall rather than leaving it all until the end - trying to top up from above is awkward once the structure is finished.

6. Top the spiral off

The peak should be the driest, most free-draining point on the whole structure. If your site is particularly exposed, a single capping stone or a large flat piece of slate at the top looks good and protects the highest soil zone from heavy rain washing it away.

Check the whole structure is stable before filling it with water. A gentle push on the sides should produce no movement - if it sways, remove courses until you find where it's loose and re-lay.

7. Plant herbs in the right zones

Top zone (dry, sunny, free-draining): rosemary, thyme, oregano, sage, lavender. These are the herbs that will struggle in wet, heavy soil and do best with good drainage and full sun.

Middle zone: basil (in a warm summer), marjoram, lemon balm, tarragon. They like good drainage but tolerate a bit more moisture than the Mediterranean herbs.

Base zone: mint (keep it in a pot or it'll take over everything), chives, parsley, coriander. These are happiest with consistent moisture and tolerate partial shade.

8. Water in, mulch, and let it settle

Water everything in well after planting. In the first few weeks, keep an eye on the top zone during dry spells - the gritty mix drains fast and new plants can dry out before they've established. Once the roots are down, the Mediterranean herbs are largely self-sufficient.

A light gravel mulch around the base of plants in the top zone helps retain what moisture there is and reflects heat back up to the plants. It also gives the feature a tidier finish while the plants fill out.

When to call a handyman

The build itself is very achievable on a weekend afternoon. That said, if you want paths laid around it, raised borders added nearby, or garden edging set to define the whole kitchen garden area - that's where Richard comes in. He can help with paving, garden edging, raised bed construction, and the heavier end of garden projects in Sandwich and across East Kent.