Mulch is marvelous. It performs a variety of functions that help save the permaculture gardener time and effort, while providing the soil and plants with a great deal of organic matter, making for healthier soil and, thus, healthier plants. Permaculture Mulching refers to the covering of areas of soil with one or more layers of material. In a permaculture garden these layers are organic in nature, and the mulch benefits the soil in several ways. Firstly, it helps to preserve moisture in the soil by protecting it from excessive evaporation. Mulch also improves the health and quality of the soil by creating a stable environment for bacteria and microorganisms to function, as well as via the nutrients in the mulch itself, which are slowly broken down and added to the soil. Mulch also adds organic matter to the soil when it is used to control weed growth. It can be used to cover a crop you wish to get rid off, starving it of light, so that it dies and rots into the soil. Furthermore, mulch can help improve the visual appeal of a garden, covering bare earth and adding texture to the ground.
There are many different ways a permaculturist can mulch their garden. However, here is a step-by-step guide to a simple but effective version that is suitable for many locations. It is intended for plots that are at the start of a transition to a permaculture garden, and for larger areas that require mulching You can spot mulch around specific plants and trees, but remember to leave some space around the stem or trunk to prevent overwhelming the plant.
Slash down any long grass and weeds. Leave the cut plants where they fall. They will add organic matter to the soil through the mulching process. Don’t worry about leaving weed seeds or roots on the ground; the subsequent layers of the mulching process will prevent them from re-sprouting by depriving them of the sunlight they need to photosynthesize.
Once the slashing of grass and weeds has been completed and the cuttings are laid on the ground, water the area thoroughly. This is done because once the remainder of the permaculture mulching layers are applied, rain won’t be able to penetrate to the soil, so this watering gives the microorganisms that will be active in the mulch the moisture they need to function.
Add some agricultural lime. This step is optional, and you need to make sure if you follow it that the lime is unadulterated with any inorganic materials, but applying lime helps to bind any heavy metals that may be in the soil so that plants – for whom such elements are detrimental – don’t take them up.
This is the layer with the most ‘heavy-duty’ material. You will need some sheets of cardboard, old carpet, newspapers or any other organic material, even old denim clothing. The key is to have enough of the material to cover the area with the edges of each piece overlapping so no gaps are left. This layer performs two functions: it prevents weeds growing (which is why you want the layers overlapping, so there is no chink for weeds to get established in) and as it breaks down, it adds nutrients to the soil. This is why it must be organic matter and not, say, sheets of plastic or metal.
Mark out paths. If you are mulching a large area you may need to access parts of it, for plantings, for instance, or to harvest fruit from trees within the area, so use bricks, stones or timber to delineate your access paths and prevent them being covered with subsequent layers of the mulch. The previous steps will still help the paths to remain weed-free and help build the health of the soil underfoot.
Add any other organic material from the garden that you may have. This could be weeds taken from other areas, small prunings, or even food scraps. Anything that could be composted can go on this layer. It will all break down, adding organic matter to the soil and building up the humus in the topsoil.
Add a layer of hay. You want to be aiming for a layer of around 15 centimeters in depth. This will get compacted over time and mingle with the organic matter below it to further augment the composting effect and so create more humus in the topsoil.
This is where you add compost. This layer could also comprise rotted manure (preferably horse manure) if you have access to it. This layer is intended to provide an immediate source of nutrients to plants that you can plant directly into the mulch. It will also, of course, break down over time and release nutrients into the soil.
The final layer will consist of more organic material, but it must be weed-free. You don’t want any weed seeds or cuttings in the top layer as they will have access to sunlight and so will be able to grow and establish themselves in the mulched area which is being mulched, at least in part, to get rid of unwanted plants! This layer could be straw, sunflower husks or rice hulls. You want to be aiming for a layer of at least 10 centimeters. This layer performs several functions. It helps to regulate the temperature of the soil, it provides nutrients, and it helps to prevent moisture evaporation from the layers below.
Once you mulch has been laid down, you can plant straight into it if you wish. You will want to give newly planted specimens a good watering, but they won’t need composting as they will be planted in one of the most nutrient dense parts of your garden.
Mulching is usually a required technique in at least some areas of most permaculture gardens. By getting a good organic mulch down, you are benefiting the soil, the plants and yourself no end.