Cover crops are traditionally thought of as plants used when the garden or field is empty, such as over winter and sometimes over summer.
But I like to broaden this definition to also include plants used during the growing season, inter-planted with food crops or even in ornamental beds where they’re sometimes called groundcovers or living mulch.
Crotalaria or “rattlepod” is a leguminous green manure often grown in the tropics. It’s great for fiber and building soil, but poisonous to large mammals.
They’re also referred to as green manures, generally when they’re going to be incorporated into the soil after a certain period of growth.
A good goal is to make sure your soil is always covered with plants, and cover crops help achieve this goal.
There’s been a lot of excitement in the last 15 years about the benefits of compost tea and nearly as much confusion about what it is.
The benefits are all the same as those things microbes do in the garden that were listed in the soil food web lesson, with insect and disease control and plant health being the main reasons people use it.
Nice with biscuits, but it won’t do much for your garden.
The confusion happens because of the name.
Gardeners have been making a form of compost tea for centuries by putting a small amount of compost in a pail of water, sometimes inside a burlap sack, stirring it once in a while for a few days, and then applying that water to the soil.
The last post was an intro to compost and now it’s time to make it.
There are many composting methods, but the most common is probably the outdoor, above-ground compost pile, and it’s a good method.
The size of the pile is important. Too small and it won’t heat up properly, but too big and it won’t get enough air. The best dimensions are three to five feet long, wide and high.
This enclosure is a good size. I just hope there’s a way to get the compost out of there!
Although it isn’t always necessary, an enclosure can keep out critters, prevent the pile drying from wind and look a little tidier.
That can be made of used wood pallets or fresh wood, concrete blocks or anything else that holds the compost in place.
Some gardeners have two or three such enclosures for different stages of the pile, such as raw materials, in-process compost, and finished compost.
Compost is our way of mimicking nature, yet speeding it up substantially.
Whereas nature slowly decomposes animal manure, leaves and other organic matter, we put a large amount of these things into a pile in specific combinations and ratios to make it happen quickly.
The forest floor is continually covered with moss, ferns, leaves, needles, tree branches and trunks in various stages of life and decomposition.
Compost is not natural. I love making and using compost, but it’s worth remembering that.
Nature makes humus by covering the ground in plants that continually grow and die throughout the seasons and years.
Masanobu Fukuoka points out in The One-Straw Revolution that we don’t need to compost if we maintain plant cover and mulch.
Despite some claims, plants and microbes really do care about the source of their nutrients.
They often do better with organic forms of the elements rather than synthetic chemical forms.
Compost is valuable for far more than its organic matter, as we’ll see later on.
While I definitely recommend using products such as lime in certain circumstances, the thing most of us need to do before all of that is start a regimen of deliberately increasing the organic matter content of our soil.
We can do this with leaves, compost and other organic materials, even cover crops.
In the last century, we’ve burned up more than 90% of the organic matter in many of our soils through tilling, applying chemicals, and clearing plant residue without allowing organic matter to decompose.
We can’t look at soil management without also looking at water management.
This lesson isn’t a complete summary of strategies, but it does cover some of the most important points we need to know.
Seedlings in the rain
While perhaps not as exciting as say, the latest fertilizer or microbial inoculant, water is more important.
Proper water management comes before these other topics and is one of the most important things we do.
Water is essential to life.
Not only do we drink it — we are made of it. Throughout the course of our life, our bodies contain between 50 and 80% water. We know our plants are made of water, too, and they need it for photosynthesis and cooling.
In 2006, I started an organic gardening service, one of the few in my city at the time that was truly organic.
This was my first chance to apply – to other people’s gardens instead of just my own – what I had learned from studying the organic approach to gardening. It was mostly successful but I had some problems dealing with weeds in some lawns and the occasional other pests.
It’s not just a matter of applying lots of everything, but small amounts of the right things.
It took me a while to figure out that it was because I was neglecting to do what is outlined in this lesson, and in some future lessons on supplementing nutrients to balance the nutrient ratios in the soil.
Most of my students have skipped this step, too, to the point where I now say, “I know you’re probably going to skip this step the first year, so all I ask is that if things don’t work for you like they should, you’ll go ahead and get your soil tested and then start to apply the appropriate fertilizers to balance the nutrients.”
Inspecting your soil isn’t particularly complicated, but there are some things you need to know to do it right.
Some of the simple tests we can do on our own, and the more difficult nutrient testing we should leave to a soil lab that can do a much better job (I’ll cover this next time).
The goal of this lesson is to outline a simple process for soil inspection.
Many of the steps can be done annually, as the real benefit of inspection comes from comparing results from year to year to see if what you’re doing is working.
What exactly should we look at?
“Such a strong symbiotic relationship exists between plans and soil that it could be argued that the plant exists to build soil rather than the soil being used to grow plants.”
–Philip A. Wheeler and Ronald B. Ward. The Non-Toxic Farming Handbook.
Before we can improve our soil, we need to know a little more about what makes it tick.
Soil gets started when rock is broken down by mechanical, chemical and biological means. This process can take thousands of years.
Nitrogen-fixing bird’s foot trefoil (lotus corniculatus) growing on limestone pavement.
The mechanical aspect of breakdown is brought about by water, wind and temperature fluctuations. The chemical aspect consists of various reactions often caused by interactions between oxygen, water, carbon dioxide and rock.
The biological breakdown process depends on the soil food web — microbes and plants working directly on the rock creating their own organic acids. This process speeds up dramatically as more organic matter is produced. They also make some of the chemicals mentioned above.
The “soil food web” refers to the inhabitants of the soil village.
They are an army of tireless workers — 20,000 to 30,000 different species of organisms found in a teaspoon of healthy soil.
The Soil Food Web inhabitants are often classified according to their “trophic level,” best translated as “who eats whom.”
We call it a web to focus on not only the different creatures living in and on the soil but — more importantly — on how they relate and interact with each other.
If you cut one silk strand out of a spider web, the whole web is affected.
Each strand is necessary, and each member of the soil food web has a role to play, too.
Some of us might enjoy getting to know what they look like, how they eat and how they move.
But more important to us as gardeners are the miraculous ways their interactions influence our garden, and what we need to do to encourage the interactions that support healthy plants.