Lasagna gardening (a.k.a. sheet mulching) is a slow composting method that is used to create and maintain planting areas. It is useful during the growing season for controlling weeds and keeping soil healthy, and it is an especially easy way to transition from lawn to garden during the “off-season.”
You can lay down raw materials for your lasagna garden as you collect them, or stockpile them so that you are ready in the fall to prep new areas for planting the following spring.
Here is how you could turn a lawn into a garden, starting as the summer winds down:
- First, mow short any existing groundcover (e.g. grass).
- Make sure to completely remove any noxious weeds (such as blackberries or bindweed).
- Loosen the soil where you’ll be creating your bed with a broadfork, digging fork, or flat-blade shovel. (This step is optional, because the worms will do a lot of this work for you during the winter!)
- Lay down a weed barrier: 10 sheets of newspaper (not the shiny inserts, just the newsprint part) or thick cardboard (avoid wax-coated corrugated, and remove as much tape and metal as possible). Make sure to overlap the edges at least 6 inches.
- Build up additional materials in 1- to 3-inch layers, alternating “browns” (high-carbon ingredients) & “greens” (high-nitrogen ingredients); 18 inches is a good thickness goal, but don’t panic if you don’t hit it. Some of the many materials that can be used are listed in this blog entry.
Put a cap layer of straw or soil on top to reduce pest attraction and encourage breakdown.
In the spring, you might have to remove a few pieces of compostables that didn’t break down, but you should be ready to prepare a seedbed and plant.
And one last tip: if you are getting rid of grass to make a new garden, make especially sure you don’t leave ANY gaps in the first few layers of the sheet mulch. Grass will find a way to come back.