Soil is the bedrock of any permaculture garden. The quality of your soil will affect the plants you can grow, how well they thrive and the harvest you can yield. The soil is also key in the health or otherwise of natural wilderness. Too often in the modern world, the intricacies and important role soil plays in the health of the planet and the productivity of an environment is overlooked. Modern agricultural practices and removal of vegetation and trees has caused many areas to suffer a complete degradation in the quality of their soil, meaning that either very little grows there, or any crop requires a lot of artificial fertilizers and pesticides. These in turn further deplete the soil of its natural goodness until eventually it becomes barren.
Permaculture seeks to preserve the unique characteristics of soils in different ecosystems. It also tries to repair damaged soil and protect it from further degradation. The primary means of doing this is to increase the amount of organic matter in the soil. Organic matter puts essential nutrients back in the soil, which in turn promotes healthy plant growth and an increase in the bacteria and microorganisms that help to transform those nutrients into forms that are available to plants. On a permaculture site there are several ways that you can ‘feed’ your soil more organic matter.
Compost is an excellent way of utilizing so-called waste material for a useful purpose in your permaculture garden. By composting food scraps from your kitchen, prunings from your trees and scrubs, grass cuttings, dead animals and, basically, anything that was once alive, you can create a rich, fertile compost. There are many different recipes for compost but as a general ule you want about two-thirds brown matter – the prunings, animal droppings and so on – and one-third green-matter, such as food scraps, leaf litter and grass. Water your compost well and make sure it is aerated, and soon bacteria and microorganisms will colonise your compost pile and turn it into useable material for adding to your soil. Compost is often a valuable addition to plantings in zone 1 of your site.
Animals have an important relationship to the health of the soil. This stems from the tiny microorganism, beetles and bugs that break up the soil to give space for plant roots to grow, water to percolate and air to circulate to the larger livestock animals who can provide manure. Animal manure is key to getting nitrogen back into the soil. Omnivorous animals for which meat can form a part of their diet, such as pig and chicken, have more nitrogen in their droppings than grazers like cows and horses, but all will benefit the soil if placed around plants. Just be aware that sometimes, animal manure may contain undigested seeds, which may come from plants that you don’t want to encourage on your permaculture site.
Organic mulches such as straw, grass clippings, newspaper and woollen clothing break down more slowly than other forms of organic matter provision, but they offer other benefits that make them incredibly useful. So, as they slowly break down, releasing nutrients back into the soil, they provide insulation from extremes of temperature, cooling the soil in the summer and keeping it warm in the winter. They also ensure that moisture is retained in the soil and that it is protected from erosion by rain and wind. And, of course, one of the main functions of mulching is to act as a weed barrier or to cover existing weeds and break them down into organic matter.
Legumes are essential for a healthy soil. They are the family of plants that have the best nitrogen-fixing ability. Certain bacteria that live in their roots convert nitrogen into a soluble form of the element that plant roots can take up and use to grow. Species such as peas, beans and acacias are legumes and by providing available nitrogen they help stimulate plant growth and bacterial activity that, in turn, helps develop the organic matter in the topsoil.
Permaculturists know that cover crops serve a lot of functions. They help to minimize water evaporation from the soil, they provide shade and, importantly, they add organic matter. This is because cover crops, such as potatoes and pumpkin, have deep roots that open up the soil, allowing water and nutrients to penetrate into it and stimulating microorganism activity. These roots also help maintain the integrity of the soil, and the leaves of cover crops rot in place and return their nutrients to the topsoil.
Green manure crops are similar to cover crops, but rather than remaining in the soil and naturally decaying in winter and revitalizing in spring, they are deliberately cut and then left on the surface or forked into the soil to add organic matter. Species such as rye grass, barley and lucerne are commonly used as green manure crops, and are slashed back several times when growing as they regrow very quickly. Just make sure you slash before the crop flowers and seeds to retain control over the crop.
Biofertilizers have been used among ancient faming cultures for centuries, but it is only recently that they have become better known among modern gardeners. Biofertilizers offer an alternative to artificial fertilizers that are potentially damaging to the soil, crops and the environment (polluting rivers and so on). They are microorganisms that are cultivated on natural material in laboratories and then added to the soil in large numbers. They help increase the biodiversity of microorganisms in a soil, they reduce pests, and, of course, increase fertility. They can also be used to heal soil that has been depleted by chemical fertilizers or exhausted by monoculture practises.
However you choose to do it, adding more organic matter to your soil is almost always a good thing. The animals in the soil will become more productive, your plants will flourish and the productivity of your site will increase. What’s not to like?