Air and water
Microbes are easy to breed. They are a hardy lot and, within twenty minutes, are hard at it.
Sound good news? The harmful microbes that make us sick, and can even kill us, breed just as fast.
No one wants to be responsible for breeding harmful microbes, so the approach with modern food has been to be as sterile as possible. But we also need beneficial microbes to regulate our bodies; they produce hormones that make us feel hungry or full, so we eat and/or stop when needed.
So the challenge is: how do we breed the beneficial microbes without breeding the harmful ones?
We do that by controlling conditions so beneficial microbes outbreed and outcompete harmful ones.
We do this with a system of flood and flush.
Water is attracted to good (hydrophilic) soils, so it does not readily move through the soil. We first need to saturate the soil so it is properly wetted, then let it drain, which is why we need to aggregate the soil so it is porous and drains easily.
As it drains, it sucks fresh air into the soil so it breathes.
But we don’t use pure water, since it has no nutrients; instead, we use what we call soil blood, which is full of nutrients.
The concentration of nutrients in the soil blood is critical. If the soil blood lacks enough nutrients, the plants will not flourish. Plants absorb nutrients through osmosis, when water moves from a weak solution to a strong one.
But if the soil blood is too concentrated, reverse osmosis occurs, pulling water from the plants and causing them to die.
This is how it works.
We catch the soil blood from the previous irrigation. This may be very dark, almost black, which indicates that it is too strong.
We need to dilute it until it is straw-coloured, a deep yellow.
We measure out the water needed for a single irrigation; there must be enough to saturate the soil, with enough left over for drainage. We learn this by experiment, but in a standard Gbiota box it is 5 litres.
We pour this onto the soil surface, typically with watering can with a rose.
This will flood the soil surface so the top layer of soil is totally saturated.
This will slowly soak down through the soil, which will absorb some water. It is like a wave of soil blood that gets progressively smaller as it moves through the soil but is large enough to reach the bottom of the box.
We may like to think our soil is nice and uniform, but in the real world it never is. There is always some channel the water can leak through without properly wetting the soil.
In a large garden bed, we use what we call a leaky dam. It prevents the water from escaping quickly, so the soil gets wetted and then drains slowly, so it drains properly.
We use the same ‘leaky’ principle in the box, but this time we make a hole in the base and plug it with a cloth, letting the soil drain slowly and thoroughly wetting the soil in the process.
This is the soil blood for the next irrigation, as it is full of nutrients, microbes, and soil creatures.
