What is a herb spiral?

Herb Spiral Northey St

I have been lucky to come across two herb spirals in the last month. Herbs that need good drainage are planted at the top of the raised garden bed. Plants which need good sunlight are planted on the side that receives the most sunlight and shade loving plants are planted on the other side.

herb-spiral-northey

Northey Street City Farm herb spiral

The first herb spiral was at Northey Street City Farm. It is approximately 1 metre high by 3 metres wide with three different levels for herbs. The top level is well drained and drier, while the bottom level is moister and cool. Different plants are planted on different levels depending on their needs.

Raised spiral gardens offer a range of micro-climates to meet the habitat needs of different plants. Raised spiral gardens are also very space efficient, and conserve water. A herb spiral can add detail to an otherwise flat or boring landscape.

Herb Spiral Qld Plant Expo

Queensland Plant Expo herb spiral

The herb spiral at the Queensland Plant Expo was smaller and probably a better size for most suburban backyards. It had only two levels and the spiral was made with stones to define the different areas. You can see they have used straw mulching to keep the weeds away.

Herbs for a herb spiral

Herbs that prefer moist conditions (plant these near the bottom of the spiral facing the morning sun):

  • Bergamot
  • Borage
  • Coriander
  • Cress
  • French tarragon
  • Ginger
  • Lebanese Cress (in a pot)
  • Lemon balm
  • Mint (in a pot)
  • Mushroom plant
  • Parsley
  • Rocket
  • Vietnamese mint (in a pot)
  • Watercress

Herbs that prefer or handle drier conditions (plant facing the summer sun and on top of the spiral):

  • Garlic chives
  • Lavender
  • Marjoram
  • Oregano
  • Rosemary
  • Society garlic
  • Thyme
  • Yarrow

No dig gardening

When we first started gardening my heart sank after I discovered the soil was full of weeds, and all sorts of different odds and ends. We decided the best solution would be to have a raised bed, filled with no dig ingredients and organic soil.

After researching all the options, we were pleased to discover Birdies Ezy Veggie Beds. We ruled out wood because we have had termites. Treated wood can leach and is not considered organic. Birdies Veggie Beds are made from colour bond corrugated steel and have a rubber edge. We ordered 4 of the 400mm x 3m x 1.5m. (I’d recommend something a little less wide as it’s a little hard to reach the centre of the bed.)

In Australia, we like to claim that Esther Dean came up with the no-dig method (aka lasagna method) in the 1970s. It’s kind of like the way we have claimed inventing Pavlovas (actually it was the New Zealanders). Mind you, she liked to experiment with different gardening techniques and then monitor the effects (like a true scientist). Low and behold, she’s still alive and turned 97 in October last year!

I would shake my head at anyone who claims that no dig is a minimum effort. Setting it up was such a big job that it took us over a month to get all four vegetable beds prepared. The hardest bit was digging up the pawpaw tree, and then moving the organic soil from the grass where it was delivered to the beds. It was humid hot and sweaty physical hard work.

Actually, our beds are less lasagna method and more spaghetti bolognese. Let me explain:

The bottom half of each vegetable bed was made up of the following layers spread evenly:

  • 1 bag of sugar cane
  • 2 handfuls per square metre of blood and bone, and rock minerals
  • 1 bag of sugar cane
  • 2 bags of cow manure
  • ½ bag Lucerne
  • 2 handfuls per square metre of blood and bone, and rock minerals
  • 1 bag of sugar cane
  • 2 handfuls per square metre of blood and bone, and rock minerals
  • ½ bag Lucerne
  • 2 bags of cow manure
  • 1 bag of sugar cane

The top half of the beds were then covered in organic soil that we purchased from a landscaping centre. We also added organic soil between some of the layers above.

The spag bolg method has all the advantages of the no dig method, but using organic soil to bulk it up helped reduce costs.

A few other tips:

  • When planning where to place the beds don’t forget to add enough space around them for an approximately one metre wide footpath. Consider mulching this area to discourage grass and weeds.
  • If placing the beds on the lawn, place ten pages plus of wet newspaper down first to suppress the grass and weeds. Sprinkle on a few handfuls of blood and bone.
  • Most vegetables have a small root system, so you only need 40cm deep of decent soil. If you are using higher beds you can fill the remaining bottom layer with clean sand, hay bales or general garden waste (minus grass seeds).
  • Alternate layers of wet (manure) and dry (sugar cane, hay, straw).
  • Blood and bone help to activate the composting process.
  • Water each layer thoroughly.
  • You can wait several weeks for the material to start composting before planting. Alternatively, plant seeds in handfuls of compost to start planting straight away.
  • You’ll need to top up the beds each growing season with lucerne, compost and/or manure.

Now the beds have been set up, we haven’t done any digging and fingers crossed that’s most of the hard work done.