Sunday, June 5, 2016

Making Humus

First I want to be clear. I am not talking about hummus, the yummy dip that comes from various cuisines around the Mediterranean. I am talking about humus (pronounced HYOO-mus). Humus is a type of soil derived from fully decomposed organic matter. It is black and rich and just about the best thing you can have for growing plants. But humus isn’t just more compost or similar. It is stable and retains itself long term in the soil.

So if it is so great for your plants, how do you get it? Well, that’s the problem. Humus is quite possibly the most valuable substance on the planet, even if nobody realizes it . Everything that supports our life on this planet, from the air we breathe, to the water we drink to the food we eat depends on humus. But nature makes it very slowly. As a kid my dad always told me that it takes nature a thousand years to make an inch of topsoil (which is mostly composed of humus). While I don’t think it takes quite that long, there is certainly not enough that it can be sustainably harvested, even on a small scale. Plus, current farming practices degrade the topsoil rapidly. Tilling in particular is very damaging to the humus.

However, we can make humus. Before we do so, there is one thing we need to understand. What is humus? Quite simply, humus is distilled from decaying organic matter. The problem is that the process of distilling the humus isn’t very efficient. You can’t take a cubic yard of fall leaves from your yard and get a cubic yard of humus. That cubic yard of leaves might give you a couple of tablespoons of finished humus. After 3 or 4 years. But it isn’t quite as bad as it sounds.

The basic formula is this:

Organic Material => Organic Matter => Humus

Organic material is just about anything that was produced by a living thing. Woody debris from plants are best. Add it to your compost bin and compost the heck out of it. The composting process removes most of the bulk that is going to go away. That cubic yard of leaves will give you a gallon or so of finished compost. Then add that to your soil. Over the next several years, that will break down further into a beautiful humus.

Now there are just three things to remember:

1) The reduction. When you realize just how much organic matter reduces to make good humus, you will join the legions of us who spend lots of time creating a huge composting operation. It really is the most important thing you can do for your garden.

2) The reason humus is so great is that it feeds the living organisms in the soil that form the ecosystem your plant is existing in. By adding compost, you are feeding the soil organisms. The fact that you are making more and more humus from the process is actually almost secondary. Feed your soil!

3) When you stop feeding your soil, the humus starts to break down and will eventually be lost. Actually, this is happening all the time anyway. It is just that regular additions of compost add humus to the soil faster than it can break down.

So go out and make more of the real black gold, the basis for our existence on this planet!

1 comment:

  1. very nice piece, enjoyed reading it.
    how big are the compost piles your working and how often do you turn them if at all?
    I've got a small worm bin going that's been producing some good vermicompost - it's some very rich organic matter.