Building Good Soil
Good Compost Equals Good Soil
Compost is the most important ingredient for building good garden soil. There are numerous products available on the market today but the best quality compost of all can be the one you make yourself.
Start by accessing which composting materials are available to you. Composting materials include food scraps, grass clippings, manure and spent plant material. You can also compost wood chips, paper, and leaves. Materials fall into two categories. The first category includes materials that are soft, or even mushy, and tend to hold moisture. Kitchen scraps, grass clippings, fresh leaves and weeds that do not develop bark tend to fall into this category, along with manure. These are the materials that are traditionally named "green" or "nitrogen rich". The second category are those materials that have bark, are harder, and tougher, and tend to hold less moisture. Wood chips and paper are good examples. These materials are traditionally named "brown" or "carbon rich".
Materials can be "green" in one stage of their existence, and brown in another stage. A good example of this is a load of grass clippings. They are "green" when freshly cut, but if they are left to dry they turn into drier more carbon rich "brown" material as some of the nitrogen is lost as the grass dries. The same hold true of herbaceous, non woody weeds. as well as leaves from trees. They may begin as green when they are fresh and full of nitrogen, but as the nitrogen is lost through drying and leaching what is left is a more "brown" or carbon rich material.
The best compost is made like a good lasagna. It has alternating layers of different types of good quality materials. Think of the green layer in your compost as the noodle layer. It should be relatively thin, and evenly spread. The filling layers are the brown materials, and just like in a lasagna, these should be layered much more thickly. I like to start the pile with a layer of sticks. These will promote better air circulation, especially as the compost begins to heat up. On top of that I like to put a layer of brown leaves at least a couple inches thick. This serves as a good base for the addition of other materials. Next add a very thin layer of nitrogen rich, or green materials. This is a good place for a layer of kitchen scraps. Follow that with another, rather substantial layer of brown materials. I like to leave a bag of wood shavings next to the compost pile to insure I have enough brown material available for use. You can buy these shavings at feed stores, just ask for stallion shavings. They are quite economical. Continue to layer green and brown, just like noodles and filling until the pile is about 4 feet high. It is best to build the pile this high all at once, and it is a good idea to use a few layers of partly finished compost from another pile in the middle of the pile in between the green and brown layers. The more different materials you use the better your compost will be. If you live in a dry climate you may have to water your pile, if you live in a wet climate it would be better to cover it to keep excess rain from making the pile soggy. If you have built it right you should not have to turn it as there is enough air in it already. The compost is ready when there are no distinguishable evidence of any green materials. It should be ready in one month in warmer climates, or in summer, but in winter it may take as long as six months, since the microbes responsible for producing compost are not as active in the winter.
Composting in Place
The simple answer to the question "Where should I build my compost pile?" is to build it right where you will be gardening. I don't mean to the side of where you will garden, but right on top of an area which you will turn into garden when the compost is finished. This eliminates the task of moving compost around, and will provide you with the best possible growing conditions. Many gardeners have stories about the plants that volunteered in their compost and turned out to be the best producing plants ever if they allowed them to grow. Why not take advantage of the fact that the best soil is always under and around your compost pile? I like to use a wire mesh ring like you see in the picture for my compost so that it can be easily dismantled and moved, and the compost spread in the area where I am going to garden.
Another method of composting in place is called sheet mulching. Some people call this method the lasagna bed method of gardening, and this is a quite accurate term because again, just as in building a good compost, building a good lasagna garden bed involves layering of brown and green materials to build a garden bed.
In this method we start with some partly finished compost. You will want your compost to be finished enough to not have any evidence of any kitchen scraps of manure, but it is okay if some of the woodier parts of the compost have not broken down yet. Lay a 3 inch to 4 inch layer of this material down in the area where you wish to garden. You do not have to remove the grass or weeds before you do this, just lay the unfinished compost right down on top of whatever plant material is there. You may want to cut the grass short, or chop the weeds into smaller pieces so that they decompose faster, but do not remove any organic material from the area. Next, lay six sheets of paper or 1 sheet of cardboard down on top of the compost. This layer serves as a weed barrier You will want to make sure you overlap the layers of paper or cardboard to seal out any light that would encourage weeds or grass. You may want to use newspaper if you are planting seeds into the bed immediately because the tiny roots can easily penetrate the paper. You can use cardboard if you are building the bed in the fall and will be planting it in the spring. You can also use cardboard if you will be putting transplants in, as you can cut holes in the cardboard that will accommodate the plants. Make sure you water the paper or cardboard layer well before continuing on.
The next layer will be the feeder layer. Use at least 2 inches of the very highest quality finished compost in this layer. Nutrients from this layer will infiltrate down through your bed, providing immediate food for the microbes below that will break down organic matter in the pile and continue to enrich your soil. The top layer of the lasagna bed is like the parmesan layer in a lasagna. Sprinkle a dusting of mulch on the bed to help hold nutrients and prevent the bed from drying out. I like to use wood shavings. No they won't tie up too much nitrogen if you have built your bed up this rich, and no they won't acidify your soil too much for ideal growth, but they will provide food for fungal organisms that can enrich your soil and offer your plants some good disease resistance. You can also use organic straw or shredded leaves for the mulch layer.
Keeping Soil and Compost Alive and Working
Your compost and your compost rich soil is now teeming with microbial action. Billions of tiny microscopic animals are living in your soil waiting to be put to work. Each group of microbes has a job description, and they ask for very little compensation in return for services rendered. Some microbes are decomposers, and continue to break down organic matter, converting our kitchen scraps and weeds into nutrients that plants can take up and use. Other microbes are like armies protecting the plant's roots from disease. Still others manufacture food for the colonies of microbes around them. Nitrogen fixing bacteria take nitrogen from the air and feed it to the plants.
Microbes, like all living things, need a good supply of moisture. We need to water our soils regularly to keep the microbes alive. Mulching, and other ways of increasing the organic matter content of your soil helps your soil to hold water. Soil that is five times higher in organic matter holds five times more water. The beauty of this is that good quality organic matter generally holds both water and air in equal quantities, thereby providing an ideal environment for beneficial microbes to grow and multiply. The plant based mulch we apply on our garden beds is a great help in keeping microbes happy. It provides protection from drying out, so is good for water retention. It also provides food, and protection. We can use leaves, wood chips, straw, or leaves for mulch. It really is a great tool for maintaining a great, healthy garden soil.
Keeping microbes alive and doing work for us is easy if we provide what they need. Just like many living things microbes all need food, water, and shelter. Many of the most beneficial ones also need air. Microbes feed on the waste products of plants, as well as any organic matter that we put in the soil. Microbes also feed on microbes, both dead and alive, including many plant disease organisms, but their main food is organic matter. Our gardens should be a continual source of food for microbes. By reapplying compost on a frequent basis, and hoeing our weeds and just letting them drop and decompose, as well as adding plant based mulch we can provide an ongoing source of food for these friendly workers who will continue to build us good, healthy soil.