How To Build a Herb Spiral
A Herb Spiral is a simple way to improve your kitchen garden, a spiral of rocks
encloses soil in which many species of herbs are planted. The rock warms and
dehumidifies the soil. The extended edge, wrapped in on itself provides a wide
diversity of conditions, creating high productivity in a small space, but is easy
to water and harvest.
Scale: A herb spiral is usually about a metre from the middle to the edge, and
the center is about a meter above the ground. This is so that you can reach to
the center from the outside. It doesn't make sense to make it smaller, because
you loose the warming effect of the rocks.
You can't really make it bigger, but its possible to put two together in a
You'll need: 1-1.5 m3 of rock, more in a humid climate; 1/4 - 1/2 m3of
compost; 20 or 30 herbs; A small amount of cardboard; Friends with strong
Construction: Choose a site close to the kitchen entrance, herbs are best when
freshly picked during cooking. The site should get sun, although its fine if part
is shaded. This should not be a spot where water pools. Lay out the cardboard
in the spiral, this will stop weeds growing up around the rocks, you don't need
it in the areas where you will be piling soil.. Arrange the rocks on the
cardboard, traditionally the spiral goes in the same direction as water goes
down the plug, i.e.clockwise, in the northern hemisphere and anti-clockwise n
the southern. The end of the spiral can be blocked with a rock, or you can
construct a small pond there, for example a tyre-pond, with a tap over it. As
you wind the spiral, you can fill the middle (see the diagram), the small rocks,
gravel and coarse sand both ensure drainage and hold heat in the soil. In
dryer climates some people just fill with soil and top with compost. When filling
with compost pile it high above the rocks, and then wash it down with a hose.
The Herb Spiral offers a variety of niche's for the herbs, at the top in the
middle is the dryest soil suitable for Rosemary, getting wetter as the water
drains down towards the bottom. Some of the spiral might be shaded by
neighbouring bushes, or if something big like bay-leaf is planted, then it will
give shade. Take up the niches between the rocks with small herb ground
covers like Pennyroyal. Rampant herbs like Basil in the sub-tropics, are better
planted outside the spiral. While the herbs are growing to full size, some of the
space between them can be taken with small annuals like Rocket.
There shouldn't really be any significant maintenance required, apart of course
from picking herbs for the kitchen. Water the herbs at the top of the spiral,
how often will depend on your climate.
Herb's and Conditions
Thyme, Sage, Aloe
Basil, Parsley, Cilantro / Coriander
Niches in Rocks: