One of the most immediately striking ways in terms of practical activity that permaculture gardening differs from common gardening and agricultural practices is that it emphasizes, wherever possible, leaving the soil undisturbed. In most cultivation techniques, tilling, Ploughing or turning the soil is a common practice, but permaculture recognizes that doing so upsets the complex ecosystem that exists in soils, involving the plants that grow in them and the organisms that live within them.
As in many aspects of permaculture design, we can see the template for the no-dig garden in nature. Natural ecosystems rarely feature an element that digs the ground, yet plants still thrive in many systems. Take a deciduous forest, for example. As leaves fall from the trees they form a ‘carpet’ on the ground, disturbed only perhaps by the rooting of animals and the efforts of the wind. Nothing other than plant roots digs down into the ground. Yet seeds germinate and establish new plants and the forest system flourishes – with no digging.
Permaculture gardeners can design to replicate this natural system, by instituting a no-dig garden bed. This is a planting bed that is layered with organic material, rather than soil, in such as way that it does not require digging. Vegetables and fruits are planted into the layered material and are able to access the nutrients they need. The labor required to maintain a no-dig bed is minimal, saving the gardener time and energy. Establishing a no-dig bed is pretty easy and can be done in almost any location.
Ideally, you would build a no-dig bed on a piece of earth or grass, but they can also be constructed on concrete, so are feasible growing options for those gardeners with, say, just a courtyard at their disposal. As your no-dig garden bed will typically be used to grow fruit and vegetables, it needs to be sited somewhere that gets a good amount of sunshine, ideally no less than six hours a day. In very hot climates you might prefer partial shade so the plants don’t overheat, but generally the more sun your no-dig bed receives the better. You might also consider orientating your bed north to south, so that the maximum number of plants get the maximum amount of sunshine as the sun moves across the sky during the day. You want to avoid a site that slopes too much as this can cause the bed to ‘creep’ and moisture to run from the higher part to the lower, depriving the plants at the top of moisture and potentially causing waterlogging at the bottom.
If you prefer you can build your no-dig bed as a raised bed, using recycled materials like boards and bricks to create a frame for the organic material inside. But you can also simple institute the bed directly onto the ground. If you are making your no-dig bed on grass or soil water the surface well before starting to construct it. It you are building on concrete or similarly hard surface it is advisable to place a layer, approximately 4 inches deep, of dry sticks and leaves, in order to assist drainage.
The bottom layer (or technically second-bottom layer if constructing on concrete) will comprise newspaper and/or cardboard. Make sure there are no glossy pages in the newspaper you are going to be use, and do not use any cardboard that has a plastic coating. Both these forms contain toxins that you do not want to introduce into your garden bed. If using newspaper, layer sheets to a thickness of around half a centimeter; if using cardboard, a couple of layers will suffice. This layer is primarily there to suppress weed growth, so make sure your sheets overlap to stop the weeds getting through. Water well.
The next layer should be made from straw. Lucerne straw is a good option if you can source it organically, as it has a night concentration of nitrogen, which is essential for robust plant growth. However, pea straw can also be used as is typically more readily available. Avoid using hay for this layer, as it will likely contain seeds that can germinate in your no-dig bed. Make a layer of around 10 centimeters deep and water the straw well.
Over the top of the straw layer is where you will place the most organically rich material. Depending on what you have available this could comprise organic compost, a mixture of soil and compost, manure from your chickens, kitchen scraps or worm castings from a worm farm. You could use all of them, if you like.
This layer should be around 5 centimeters deep and, like the previous layers, needs to be well watered when complete. Keep some compost mixture aside for your planting holes. Obviously, using the measurements above might not bring the no-dig bed up to the level you want (for instance, you may want a higher bed to avoid bending over when it comes to harvesting), but rather than making thicker layers, repeat the layers, straw and compost, using the same proportions, until you have the desired height.
However many layers you institute in your no-dig bed, the top layer should always be straw. This acts as a mulch to keep weeds down and to retain moisture within the bed. Again water this layer when it is laid.
Make Planting Holes
Having completed the layering of your garden bed, it’s time to plant. Make holes in the top layer of straw not quite down to the underlying compost layer. Fill the holes with some of your compost mixture, and plant your seeds, seedlings or plants. (Space your holes according to the space required by the mature versions of your preferred species, but consider integrated planting to maximize yield from the bed. Also, think about companion planting to give benefits to your vegetables and fruits, such as shade plants or insect attractors as required.) Water the plantings well.
Over time the layers of the no-dig bed will break down as decomposition takes place. To keep your plants provided with nutrients, add layers of compost and straw as the previous layers break down. You can also add a deeper layer of straw to the top if weeds or moisture retention become a problem. The straw should keep the bed moist, but make regular checks and irrigate if the bed dries out.