With just two basic “ingredients,” you can create rich soil in a garden or raised bed this winter to plant in the spring.
Those ingredients are nitrogen and carbon, which create compost.
Layering them like lasagna, a process also called sheet mulching, is a very simple way to create beds without having to move heavy loads of finished compost, especially in a place with poor soil. Winter is the time to do it because the ingredients need months to break down.
Sources of carbon include dead leaves, straw, pine needles and wood products like chips, ash, sawdust and paper. Nitrogen is commonly added to compost through animal manure, kitchen scraps, coffee grounds, green plant waste and seaweed.
When you’ve cleared a site for your lasagna bed, break up the soil with a shovel or spading fork to create some drainage, then put down several layers of uncoated cardboard or newspaper. When the growing season starts, this layer will stop weeds underneath from growing up into your new bed.
Lasagna composting also works in raised beds.
Water the paper layer to give the composting process some moisture, then add alternating 1-inch layers of nitrogen and carbon. Three feet of material is a good starting point. As the decomposition process starts, you can continue adding more materials to the top, always ending with a carbon layer so bugs don’t lay eggs in the richer nitrogen.
Typically, it should take about six months for the bed to create soil, although the process could take a bit longer, depending on how many layers you made.
It’s ready for planting when the layers have broken down into soil, and you don’t recognize the original ingredients you added. If the process isn’t done by springtime, you can add a few inches of prepared compost on top and let the rest continue to decompose underneath.
Some words of caution: Home compost piles don’t get hot enough to break down meat or dairy products, and adding plant waste from crops that were diseased, especially tomatoes, can transfer the disease to future beds. Hay is not a great choice for adding carbon because it’s likely to have seeds in it that result in weeds.
