It is a method that really works. I have recently tried it and it was more than satisfactory. It is placing layer upon layer of disposable material in sheets and letting it decompose over winter until spring. Voila! A garden with high nutrient content and the ability to retain moisture. No intensive labor. It is a no-till garden unless you decide to dig a small area of soil out for placing the first layer.
Pick a spot with full sun exposure as these gardens are usually used for growing vegetables. Lay heavy cardboard over the area selected. Overlap the edges of the cardboard. It can be a spot that is grassy, stony, sloping, bare or weedy where nothing would previously grow. You can also use newspaper instead of cardboard putting it on about eight or 10 layers thick.
Then comes a variety of several items of your choice. This first layer is called brown composting material. It can be hay, straw, wood chips, fall chopped leaves, shredded paper, small woody cut up branches, manure or peat moss. Layer this to about 3 inches thick. Then add green composting material next such as grass clippings, vegetable scraps and any leftover degradable scraps from the kitchen, fruits, vegetables, peelings, etc. (no meat products). Coffee grounds, egg shells, weeds and leaves are also green matter.
Continue layering rotating brown and green until it reaches a foot or more in height. Do not repeat the cardboard.
Boards or some support should be placed around the area to contain it. This will keep the potential garden from becoming and looking messy. Besides boards, rocks, bricks, logs and any other items can be used.
Water each layer thoroughly as you progress. Sprinkle the top with a little bone meal and wood ashes. Do not stir. Keep watering until frost. It is then left to sit until spring when it will have shrunk to about 6 inches.
I like to put a few inches of soil or potting mix on top before seeding or planting transplants. The composted garden can sometimes be so light, the plants and or seeds can sink too deep and prevent proper growth.
I had a problem with labor in confining all this material until I thought of a solution. My soil is extremely sandy and digging is easy, so I dug the area about 6 inches down into the ground before I started layering. This can work for heavy soil as well. When it is decomposed the layers will be about even with the surrounding soil.
This garden will decay quite readily and you would need to add more material each year with the exception of the cardboard.
Betty Winscher is a Master Gardener Emeritus and can be reached at (320) 584-8077 or via e-mail at [email protected]