Soil is the foundation of any garden, and even more so of a permaculture garden.
Well fed, well maintained, little worked, it remains alive and fertile, and this in a sustainable way: here is how to take care of the soil of the garden.
Read also :
- Permaculture, definitions and main principles
- Permaculture, biodiversity and autonomy
A living and fertile soil
The forest floor as a model
Permaculture is based on an essential principle: a living soil, nourished by regular inputs of organic matter, is naturally fertile soil.
Take the example of a deciduous forest: man does not have to act on the soil for the forest to be productive. The dead leaves that fall in the fall and decompose on the ground thanks to the scavenging organisms are transformed into humus; this humus allows these same organisms to live and it fertilizes the soil.
The following spring, the tree draws from the soil to produce new leaves, which in turn will fall, returning to the ground what they took from it during their development. The cycle is immutable, and the equilibrium occurs without human intervention.
No chemical fertilizer but compost
In the garden cultivated in permaculture, it's the same thing! Chemical fertilizers are banned. At most, we can buy a little manure or compost if we do not have enough, but the idea is to systematically recycle the material produced on site, so that the waste of some is the resources of others. In short, we must give back to the earth what it has given us. This is where compost comes in: composting is essential in permaculture.
Very limited tillage
The ground is not a mere thickness of earth. It is made up of different layers - called horizons - which each have their own particularities, and which house living beings (fungi, insects, earthworms, mites, bacteria and other micro-organisms, etc.). It is these living beings that transform organic waste into humus and then into substances that can be assimilated by plants: without them, the soil is dead, it becomes exhausted, becomes sterile.
However, to plow, to work the soil in depth, worse, to turn it over, it upsets this balance by mixing the different layers: the soil suffers. In a forest, the ground is never digged, and it is doing very well! In permaculture, we are happy to aerate it with a grelinette: this minimally invasive intervention for the soil does not destroy the soil fauna and does not mix the different horizons. And the gardener will not complain: it is so much less work!
No bare ground!
Nature abhors a vacuum, permaculture too! Leaving the ground bare is seldom beneficial. The first thing is therefore to optimize the succession of crops and replant as soon as a place becomes vacant. But this is not always possible or sufficient: some tricks allow you to cover the ground.
Permariculture and soil mulching
Never leaving bare soil, both between two crops and at the foot of plants, has 4 main advantages:
- limit the evaporation of water and therefore keep the soil cool for longer (which also means less watering),
- prevent erosion and leaching of the soil by runoff of rainwater or watering,
- promote the natural life of the soil - even nourish it -,
- curb the development of weeds.
Install a mulching organic rather than mineral mulch allows all these advantages to be combined. By decomposing slowly, the mulch will help provide humus to the soil. The soil can be mulched with semi-ripe compost, green waste passed through the shredder, BRF (fragmented branch wood) from the size of hedges and trees, grass clippings, dead leaves, or even brown cardboard (with as little ink as possible).
In permaculture, we can also cover the soil by composting the waste directly on the ground: this is surface composting.
In practice, the soil at the foot of the plants is covered with compostable waste mixed with straw, and the whole decomposes on the spot. We thus simultaneously benefit from the advantages of composting and those of mulch!
Permaculture and green manures
Green manures are also a good solution for structuring and aerating the soil thanks to their root system, covering and protecting it, and fertilizing it after mowing (especially with green manures made up of legumes such as mustard, faba bean, vetch, peas, etc. clover, which capture nitrogen from the air and store it in root nodules, which represents a long-lasting supply of nitrogen when the roots decompose).
Also read: green manure, think about it!
Cultivation on mounds, on straw bales, in lasagna
Permaculture also uses original cultural techniques, allowing the cultivation of vegetables, aromatic plants and even annual flowers on any soil. Whether the soil is poor, shallow, too wet or not enough, or even totally unsuitable for cultivation or non-existent (in the city, for example), there are ways to recreate fertile soil, by forming a bed rich in organic matter:
- Cultivation on straw bales: plant by installing the plants in pots directly in straw bales that have been watered beforehand in order to start their fermentation;
- Cultivation on lasagna: we pile up successive layers of nitrogenous and carbonaceous organic waste - household vegetable waste, cardboard-, and we plant after a few weeks, when the organic matter has started to decompose).
Cultivation on mounds (also called cultivation on teens) improves soil that is poor or too wet, and the soil warms up faster. This is a sustainable technique compared to the previous two, which must be renewed each year.
Read more: Permaculture, self-sufficiency, autonomy and profitability
Photo credit: Fotolia, kaliantye