Sheet Mulching in your Garden

Sheet Mulching doesn’t mean adding an old Snoopy sheet to cover up your weed patch! Many gardeners ‘sheet mulch’ an area of their yard where they plan to grow flowers or vegetables in the following season. By adding a few layers of organic matter to a fallow or weed-infested area, you’ll be sending a mostly invisible band-of-brothers down into your soil shouting, “Come party with us!” to all the fungal, microbial and insect life underground. You’ll magically be improving your soil without adding any chemical fertilizers. Sheet mulching the area will improve the well-being of all future plants in that area and consequently they will have far better resistance to diseases and pests.

A fantastic time to sheet mulch is in the fall so that organic matter is decaying for about two seasons. By early spring you’ll be able to plant and have a healthy, prolific yard. If you’ve been thinking about removing a front lawn or part of a lawn so you’re wasting less water and using fewer chemicals, sheet mulching is for you! Don’t physically remove your lawn. Simply mow it and add your sheet mulch layers right on top. If you’re new to this garden or your yard has been sloughing off not doing a thing, you may want to do a soil test first. Many good soil testers are available at local nurseries or at GrowOrganic.com.

• Step 1: Trust and Trample

Chop down any tall weeds. Do not pull them out of the ground as this will wake up all the weed seeds hiding in your yard. Simply step on them or chop them to the ground and leave them there to decompose naturally. (If a few weeds have gone to seed, gently pull out only those and toss out.) Remove any large woody materials, as well.

If this is a lawn or part of lawn, simply mow the area and leave grass clippings on the lawn.

• Step 2: Add a Concentrated Layer of Compost

Add several inches of enriched compost or aged horse manure or worm castings to the top of the soaked soil. This is high in nitrogen and will wake up the microbial life underground! If your soil is hard clay you may want to add some gypsum at this time. If your soil is very acidic, you could add a layer of limestone. The package will give the correct amount to add per square foot. (Add any other soil amendments your soil test kit suggested at this time.)

Thoroughly soak the ground with water.

• Step 3: Add an Organic Weed Barrier

This barrier will prevent germination of the troublemaker weed seeds and their cohorts by taking them to the dark side! You’ll want to make sure they never see the light of day again, literally. The weeds and grass will die and become food for earthworms. This weed barrier will eventually decompose.

You have a few options: newspapers, cardboard, burlap bags, gypsum board or even worn-out jeans.

Most gardeners choose newspapers or cardboard. (Cardboard will take longer to break down.) Lay out 4-6 sheets of newspapers thick or single layers of cardboard along the entire area making sure each piece is overlapping with the next. Do not leave any soil exposed to light. If you are sheet mulching around any existing plants, make sure to leave a few inches between the plant and mulch.

• Step 4: The Final Layer

This layer mimics the top layer of the forest. Add a 3-4 inch layer of mulch such as leaves, wood chips or straw. Avoid using hay as hay has many weed seeds. Water weekly if no rain is expected.

Come spring, you can plant directly into your sheet mulch, as it should be fully decomposed. There will be no reason to turn the soil here since you hired the earthworms to do the work for you already. Isn’t nature grand! After planting flowers or crops, you may want to add a new top layer of mulch to keep plants cool in the summer and warm in the winter.