How to Build an Herb Spiral

by Erin Marissa Russell

Ready to build an herb spiral? You’ve probably admired the whimsical layout and space-saving design of herb spiral gardens on Pinterest, gardening websites, or maybe even in a neighbor’s yard.

Whether you have a bulletin board full of sample clippings or this article is your introduction to the herb spiral, we’ll take you through the steps you need to follow to build your own. First things first: You’ll need to choose whether your spiral will be a flat design or a multilevel miniature herbal mountain.

The multilevel design is most true to the roots of this type of herb plot, but many gardeners have found success with the flat design, which is simpler to install. The herb spiral planting concept, also called an herb snail, is based on a Japanese philosophy. It takes advantage of what gardeners have learned from observing how nature works when these herbs grow wild.

The mounded spiral shape echoes the height differences between the landscape’s climate zones in miniature. The best part of the vertical spiral design is that it puts the plants’ natural preferences to use in your garden, ensuring the best possible crop for your herbs.

Even if you opt for the simpler single-level construction, your herb snail will be a beautiful and unique focal point in your yard or balcony. Depending on your growing zone and the plants you choose to grow, you may be able to depend on your new garden bed for herb cuttings year-round.

Select the Optimal Spot for Your Herb Spiral

In most locations, the best place in your yard or balcony to build an herb spiral is a sunny spot that’s conveniently located close to your kitchen. That’s because you’ll quickly become dependent on being able to snip fresh herbs from the spiral to enliven all your dishes. You won’t want to hike out to the far reaches of your yard every time you’d like to add some rosemary to roasted potatoes or cut basil to make a fresh pesto.

Consult the packets of seeds for the herbs you’ve chosen to check whether your growing zone will require an especially sunny area. In temperate places, your herb plants will flourish in a spot dappled with plenty of sunlight.

Whatever your location, aim for at least five hours of sun per day when you choose where to create this garden feature. But if you live in a place where summers are scorchers, you won’t want the afternoon sun to beat down too strongly on these plants, which can sometimes be delicate. The circular shape of the herb snail, though, means that plants that prefer more shade or moisture can be placed where they’ll thrive.

Plan the Best Schematic for the Herbs You Want to Grow

When you’re setting up the layout of your spiral herb garden, there are two components to consider when choosing where each plant will be placed.

First, the cardinal direction each side of the spiral faces—north, south, east, or west—will determine how much sun the plants on that side will receive. Then, if you’re building up vertically to create your herb spiral, you’ll need to think about the height of each plant, as it impacts how much moisture the soil in that area will hold.

If your spiral will have multiple levels, make sure that the lowest point where the spiral begins faces north, with the highest areas facing south. Even in a flat spiral, the western face of the circle will be a hotter area that gets plenty of sun, while the eastern side gets the gentler rays of the sunrise and milder morning.

In addition to water’s natural tendency to seek lower ground, you may choose to use different types of planting material on each level of a mounded spiral. That means each level will mimic a different part of the world, so plant herbs in the area that most closely resembles their homeland.

The top of the spiral will be your Mediterranean, with the driest soil (or sand) and plants that will get the brightest sunlight. Oregano, rosemary, thyme, and other woody herbs grow well in this microclimate.

The center level, though the soil will still be well-draining, will receive a little more shade and protection from the sun. More fussy plants that depend on plenty of shadow or need plenty of moisture and compost should be planted on the lowest level of your spiral.

These include those that grow in cooler areas, such as cilantro, comfrey, and mint. You can even put plants that grow in the water in the very bottom tip of the herb snail, which we’ll call the pond.

For a Flat Single-Level Herb Spiral

While a flat herb spiral won’t give you the microclimate benefits that the multilevel design will, you’ll still be taking advantage of the spiral’s naturally space-saving shape. Whether you’re installing your spiral directly into the yard or on a patio or balcony, follow the steps below for a multilevel spiral, with the exception of building up the walls. You’ll still have a beautiful garden feature that packs plenty of herbs into one lovely area. A spiral six feet wide holds as many plants as a 25-foot straight garden bed.

For a Multilevel Herb Spiral

If you have the time and materials to build up when you create your herb snail, we recommend taking advantage of the benefits that go along with multiple levels. Follow the steps below to build your very own herb spiral garden.

Map Out Your Herb Spiral Plot

First, use a pole or stake to mark the center of your spiral garden. With a measuring tape, plot out the length of string or rope you’ll need to mark the edges of the spiral. You’ll want the rope to be half the width of your spiral, or its radius. Affix one end of the rope to your stake, then hold it taut and spin it around the stake while marking the edge of your bed by digging a small trench with a stick, then placing stones to mark the spot. Use a smaller length of rope to mark out the edges of each level.

Place the Bottom Layer and Prepare the Ground

This next step isn’t required. If you’re adding an herb snail bed on top of your lawn or another area where plants already grow, it can help choke out those plants to make room for your herbs. Using cardboard, gravel, or geotextile (weed-blocking garden mat fabric), create a barrier to serve as the bottom layer of your herb spiral.

Whether or not you’re using geotextile, you’ll want to remove any weeds, grasses, or other plants that are in your herb spiral’s space. Use a rake, spade, or shovel to break up the soil and ready it for planting before setting down your bottom layer as discussed above, or if you’ll skip it, before building up your spiral. If your spiral will include a pool at the bottom point, dig more deeply where you want your water feature. You’ll need to use a pond liner at the bottom of your pool.

Build Up Your Herb Spiral Walls

Whether your herb spiral walls will be made of brick, stone, or wood, follow the markings you made in the first step to lay them out. If you’re using a natural material that varies in width, place the widest stones or sticks at the bottom of your spiral, working your way up to the thinnest materials for the top. The walls should slightly slant toward the middle of your spiral so they don’t topple outward when you add the interior soil. The highest point of your herb spiral walls should be about a meter from the bottom.

Remember that bricks or stones will get hot in the sunlight, so don’t place plants that can be burned too near the edges of your garden. Keep in mind that your plants will increase in size as they grow, so make sure your schematic leaves plenty of room for them to expand before overlapping the edges of the spiral’s walls.

Add Your Soil and Plants to the Herb Spiral

Fill the interior circle of your spiral about halfway with gravel or other material to encourage draining, such as broken pots, rubble, or sand. Add your potting soil mixed with aged manure or compost to fill the spiral shape. Then place your herb plants in the positions you’ve plotted out in your schematic. Leave 10-20 inches between each plant so there’s room for them to grow.

Now that your herb spiral is installed, the fun is just beginning. Your herb snail garden feature will provide you with a crop of fresh herbs for cooking or medicinal uses. It also takes advantage of the principles of permaculture. You’ve reflected the way nature takes care of these plants to make your work as a gardener have the biggest payoff. So sit back and watch the fruits of your labor thrive.

Want to learn more about how to build herb spirals?

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