Want to make your own vertical herb spiral garden? This compact space saving design can be made with just a few basic steps.
Construction materials and methods vary so after deciding on the best position and gathering your materials, you can have one built the same day.
Think of this as a typical ‘recipe’ you can follow, substituting ‘ingredients’ you have handy. If you like this particular design, here are some basic instructions for making a gabion wall or visit BlondeMafia or Garden Drum. Instructional videos for gabions are here and here. For the tutorial steps, read on!
Materials you’ll need
- Cardboard (without ink or tape), weed mat or gravel – optional but useful to kill weeds if building your spiral straight on top of lawn. (I avoid carpet because it’s likely been treated with chemicals that will leach into the soil as it breaks down). Alternatively, you may need a drill for drainage holes if building on concrete.
- Long stake. Secure a 1m length of string to the stake and tie at the other end with a lightweight stake, bamboo cane or chalk. Use this to draw a line on the ground to measure out the circle.
- Organic matter such as mushroom compost, worm castings, lucerne, mulch, straw and garden soil to build fertility to feed your garden long term (quantity depends on diameter of your spiral).
- Compost (for planting your herbs into – preferably homemade so it will be full of living microorganisms or alternately, a certified organic compost).
- Rock minerals and organic fertiliser (to add nutrients to your soil).
- Mulch (whatever you have available) e.g. lucerne, sugarcane, baled grassy mulch hay, pea straw, grass clippings, leaves, etc.
- Herb seedlings; bay tree and vegetable seedlings if planting.
- (Optional) pond materials and irrigation fittings if including.
Orientate your pond or bottom of the spiral on the southern side in the Southern Hemisphere and northern side in the Northern Hemisphere. When it comes to planting, this will allow you to position your plants according to their sun, shade and water requirements.
How to Build Your Spiral
STEP 1: Measuring up – Have someone hold or bang the stake into the central point of the ground where you want to position your herb spiral. To determine the perimeter, stretch out the string attached to the centre stake to mark out your circle, drawing a line in the soil with the other stake or bamboo cane tied on the end of it (or use chalk if you are marking out a hard surface).
The diameter averages between 1.5 – 2m (5 – 6.5 ft) or 750cm – 1m (2.5 – 3.25 ft) from the centre.
Tip: If building straight on top of concrete, make sure you drill holes or have adequate drainage.
STEP 2: Your base – if starting on lawn you will need to stop weeds from growing. Cardboard can be used for this purpose to sheet mulch and build the spiral on top. No light = no weeds! Some people use newspapers or thick phone books instead but I choose to avoid adding anything to my organic garden with inks that may be based on genetically modified soy beans. Cardboard edges need to be well overlapped to block all light.
Lay your weed mat or wet cardboard (soak with a hose or in a wheelbarrow) to cover the circle you have marked out. Cardboard will breakdown and add carbon to your soil and provides a food source for microorganisms. You may also choose to add some organic matter under this to accelerate breakdown of the cardboard such as chopped vegetable scraps and other green waste from your garden.
STEP 3: Construct the wall structure – Using your edging material of choice, start laying your bricks/rocks on the outer edge and working inwards to create a spiral shape, allowing about 0.5m (1.6 ft) width to plant into or adjust if making a smaller spiral.
For a more formal look, use mortar or cement between your bricks or stones.
Tip: Save your best looking materials for the outside ‘face’ and those that will not be seen on the inside of the spiral.
If using heavy rocks or stone, you may prefer to dig a shallow trench around the circumference of the circle and lay these into it on top of a layer of cardboard or weed mat to prevent weeds. If using the dry stone wall method, you may find it easier to add your organic materials as you go to provide support rather than adding these at the end for the mortar method.
Once you have your basic shape laid out around the circumference, add a second tier of bricks, remembering the outside ‘wall’ of your spiral is lowest (e.g. 2 bricks high or perhaps 1-2 rocks depending on size – enough to retain your soil).
The middle will usually end up about 1m (2.5 ft) high with a central planting area, gradually tapering down in height on a light slope to the bottom. You can block it off or add your bog/pond at the base if using.
STEP 4: Add your organic materials & nutrition – for each of us this will be different, depending on what you have easy access to. Some people only add mulch or straw to their herb spiral and plant into pockets of compost. If you’re on a tight budget or this is all you have access to, then this system of ‘growing soil’ will work fine but ‘dead dirt’ is unlikely to bring you a successful outcome!
“Like humans, plants thrive on good nutrition.”
Rather than buying in a trailer load of soil from your landscape yard, you can make your own soil teaming with living microorganisms. Soil that has a good structure (a crumbly fine texture that holds moisture well) is ideal for healthy productive plants.
These organic ingredients are likely much cheaper than buying in soil too!
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Good sources of organic matter that will build soil fertility include:
- well rotted manure
- mushroom compost or even better, your own compost
- worm castings from your worm farm
- moistened coconut fibre; and
- for lower layers use materials like leaf litter, well chopped prunings and dry grass clippings.
Sprinkle rock minerals (crusher dust from your landscapers is also suitable and very economical) and organic fertilisers as you add the organic matter to build in nutrients as a food source.
If you have access to biodynamic preps you may choose to add these too. To assist breakdown and ensure there is enough moisture, water in each layer with liquid seaweed. Expect some natural settling to occur.
Moisture loving plants at the bottom of the spiral will thrive if you include some (optional) additional moisture holding ingredients like coconut fibre (coir peat), sphagnum moss, worm castings or some well aged compost (humus).
How to Videos & Resources
These videos focus more on constructing the spiral structure than building the soil but I think you will get a better idea watching several spirals being built – they all offer different perspectives and insights!
Watch how to build your soil to feed your plants in a herb spiral, to meet their individual needs (the video quality is not great but the information is helpful!)
This video covers a Permaculture group building a spiral with straw and planting into pockets of compost.
This video shows a spiral made using rocks and soil.
Dean Chichelli from The Nature Learning Center shows how to build a Spiral Herb Garden – he mainly uses straw and then plants into pockets of compost at the end.
This last video shows how to build a very compact herb spiral with bricks.
Diagramatic technical specifications plan – Full size printable.
Tips for Building Your Herb Spiral
- To fill gaps in the perimeter curves of your spiral, use small, cut or broken bricks and stones.
- You can fill niches with ground covers like oregano or pennyroyal. Sphagnum moss can be pushed into gaps up the wall and a small amount of compost tucked inside to plant into. Or make a seed ball with some compost, a little clay and moist coconut fibre (coir peat) rolled up with seeds inside and push against the wall into the crevice. When the seeds are moist they will germinate and grow into the gaps.
- Finish with decorative and smaller stones, rocks or bricks at the top.
- To add a water garden at the base, dig out a hole and add black plastic to line it. You can use any container that will hold sufficient water and grow water loving species like water chestnuts and cress. Alternatively if you live in a dry climate, use the ‘pond’ as a reservoir to water the garden from.
Before & After – Some Inspiration!
Check out the Herb Spiral photo album on Facebook for more inspiring ideas.
Really cramped for space? You can still design a mini sized herb spiral!
In How to Plant out a Herb Garden, I share a herb plant list to make it easy for you to know what to plant where in your herb spiral and tips for laying it out.
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