Sheet mulching is a really handy permaculture technique for building new gardens (and improving/rejuvenating old ones). You may have heard of “Lasagna Gardening.” That is a nifty name for sheet mulching.
There are several advantages to sheet mulching.
- Sheet mulching requires no digging. This is handy if you don’t know where your utility line locations.
- Sheet mulching beefs up the soil with organic matter and nutrients. What an easy way to feed your plants.
- Sheet mulching smothers weeds and grass, so you can build no-dig gardens right on top of the grass.
- Sheet mulching is easy and can be done at any time.
There are a few standard steps to sheet mulching. Let’s take a look at how it’s done.
The first layer is some sort of compostable barrier, such as paper or cardboard. I have used newspaper, cardboard and paper grocery sacks. This layer should be something that will decompose over time, allow plant roots to grow through and allow worms to come up from the soil below.
It is important to soak the paper (or what ever) with water. In fact, you should water each layer as you build your garden. Since the wet layer of paper smothers what ever is under it, be sure not to cover plants you want to keep. It is best to use cardboard in the Fall (so it has time to decompose). I also like cardboard covered with straw or wood chips for paths.
I use a thick layer of straw or leaves for the second layer. When forming the second layer, it may be necessary to mix or turn over the straw/leaves while watering, so that they get thoroughly soaked. Straw (not hay) is really cheap and can be purchased at nurseries or feed stores. Leaves are free and can be collected in the Fall. If you can shred the leaves, it’s even better. They will decompose faster.
You can use other garden waste too, as long as it wasn’t sprayed with herbicides.
Warning: Don’t use poison ivy, poison oak or poison sumac in sheet mulching. The compound that causes itching (urushiol) does not degrade in the soil.
The third and fourth layers are compost, topsoil, amendments, and the like. If you have composted manure (cow, horse, bunny, chicken, etc.), you can throw some of that on too. Don’t use raw (non-composted) manure unless you are building your garden in the Fall (so it can compost over the winter).
If you want, you can stop there. Lately, this is the most sheet mulching I am doing, since I have a lot of ground to cover and not much to cover it with.
If you like, you can add one or more additional layers, as shown above.
It is OK to mix up the layers with a garden fork.
I always top off with a thick layer of straw. This suppresses weeds. To plant, I move some of the straw away from the location I intend to plant a seedling. I dig a hole, plant the seedling and firm up the “soil” around it. When I am finished, I move the straw back, forming a well around the seedling. If you cover your seedling with straw, it won’t grow well and may die. Finally, I give the seedling a good drink of water (even if the garden bed is already wet).
As the straw and/or leaves decompose, you might notice your garden “deflating.” This is OK.
You may also notice an increase in garden fauna, particularly wolf spiders, moths and worms.
Here is one of my gardens (the berm) made by sheet mulching.
If you are interested in learning more, just do a quick Google search of “sheet mulch.” You will find lots to useful articles and YouTube videos to get you started.