Sheet Mulching

Sheet Mulching

Although I consider myself an amateur gardener, I regularly have friends asking me for advice in starting a garden. It can feel like a daunting task; chopping sod, finding someone with a rototiller and tilling the ground, or building raised beds and hauling soil, figuring out what to add to the soil, figuring out how to sow and tend to each plant. The entire months’ long project can feel more like a “fly by the seat of your pants” experiment. In light of this daunting and unpredictable adventure, many garden starting attempts are procrastinated for the next year, and the next, and…

It does not have to be this way. A simple, cheap and resourceful alternative is to use a technique called sheet mulching. Sheet mulching is basically composting in place, on your garden bed. It is also called sheet composting. It is a technique useful for existing gardens as well as a very accessible, easy way to start a new garden plot. Sheet mulching mimics nature by accumulating and breaking down organic matter from the top down. It is highly effective for building nutrient rich soil and for eradicating unwanted vegetation; weeds or grass.

So, why it is so effective? Have you ever noticed when you empty your compost bin (this only applies to bins open to the ground) that about a foot of soil under your bin is what could be called “black gold?” It’s dark, moist, sweet smelling soil teaming with healthy organisms. This is because as your compost pile decomposes, minerals seep into the ground below creating vibrant soil. With sheet mulching these nutrients seep straight into your garden bed where they are immediately available to the roots of your garden plants resulting in healthier plants as well. This is why sheet mulching is a great way to enrich existing gardens as well as a strong start for a new garden bed.

All right, let’s discuss how to sheet mulch. First, pick your bed, whether existing or not (if it is a new bed, cut the existing vegetation very low and save it). Then, water the area well. The soil needs to be very moist to support plant growth, and this is hard to do once the sheet mulch is in place. Next, before we begin placing the layers, it is beneficial to lightly aerate and loosen the soil with a garden fork. Once loosened, the base layer can be either cardboard or newspaper. The cardboard should be non-waxy with no tape and little print. Furniture stores or recycling dumpsters are a great source. If using newspaper, do not use glossy papers as the inks often contain heavy metals. When laying the base layer, be generous and overlap the edges. This base acts as a weed suppresser, so one-eighth to one-half inch thickness is great. Once this is in place, water thoroughly until it is saturated. Now begins the more familiar process of creating a compost pile. Beginning with a thin green layer, alternatively stack brown and green layers in a ratio of 25:1 to 30:1 respectively. Green materials are nitrogen rich matter such as manure, fresh grass clippings, small kitchen scraps and restaurant or grocery cast-offs. Brown materials are carbon heavy items such as loose straw, hay, yard waste, leaves or others. Continue applying water to each successive layer as you go until reaching a damp-but-not-wet state. Great sheet mulch can vary from one to two feet high depending on the brown and green matter used. On top of the final brown layer, apply a couple inches of compost or a soil/compost mix. Now top this with a two inch seed-free mulch layer. You can now start seeds in the compost layer by pushing the mulch slightly aside or transplant starts by poking holes down all the way through the base cardboard or newspaper and placing transplants with soil partway in the hole. That’s it.

Sheet mulch can be applied in either spring or fall. It not only is a fantastic way to boost the health of your soil, it is also very effective for retaining water and slowing down evaporation. Both the sheet mulch and the resulting soil will require less water consumption. Sheet mulching, like many gardening techniques, can be approached causally or attentively which will influence both fertility and decomposition time. As gardening quickly teaches, soil health affects everything. Sheet mulching is nature’s very own technique for building thriving soil abundant with life. All of the ingredients are free. In fact, it is a great way to reclaim valuable resources from our waste stream. So don’t deprive your garden or yourself another year. Get growing!

Article by Brandi Mayes

Leave a Reply