Make a New Garden Bed With Sheet Mulching
What Is Sheet Mulching?
Sheet mulching is a fast, labor-saving technique for building new planting beds and suppressing weeds.
Is there a section of your lawn that you'd like to turn into a bed for ornamentals? Or perhaps it's time for the new herb garden you have always wanted. Creating a new planting area with sheet mulching may just be the answer.
Instead of picturing what you need to remove from a certain spot of field or lawn to build a garden bed, think about what you can pile on top of it that will smother the weeds or grass. The best cover is something organic, that will eventually form part of the soil while suppressing the unwanted plant cover.
The covered greenery will die and decay over the course of some months, helping to build rich, loose soil that's ready to plant. The process closely mimics nature’s own soil-building process.
The best time to create a new bed with this method is in late summer or fall. If you start in the fall, it will be ready to plant by the next spring.
The First Step
Killing the Grass
- The first step is to mark the perimeter and place an edging around the bed. Build with wood, blocks, or bricks, about 12 inches high. Make sure its secure and strong enough to hold your new garden.
- You do not need to remove the existing sod or weed cover. Just cut down any taller growth, or mow the grass, and leave it there. Any vegetation you cover up as you build your new planting area will soon decompose and add vital minerals and texture to the soil's nutritive value.
- You may need to add a thin layer of soil amendments depending on your soil type - gypsum or lime and rock dust.
- Now, cover the bed area with a layer of cardboard or layers of newspaper. This layer will prevent any weeds or plants from growing up. Do not use the shiny or colored pages as they won't decompose as well.
- Make sure you don't leave any gaps, as weeds or grass from below could grow right through.
- Use a garden hose to soak each layer before you place on the next one. The water will speed up the decomposition. These layers of paper add some necessary carbon to the soil in your new bed as it decomposes.
Make the bed narrow enough so that you don't need to walk in it to weed or plant. Walking on your planting beds will compact the soil, so air and water can't penetrate. This will cause root stress.
An alternative is to put down flat stepping stones or rounds of wood so you have something to walk on, and make the bed around them. Put them on top of the paper layer, and make sure they're big enough to stick up through the mulch you are going to add.
Build Up the Soil
- Begin with a high-nitrogen layer about 8 to 10 inches deep. It will pack down, so don't skimp on it. Get a little creative with this first layer of mulch. Use whatever organic materials are available to you. Thinking that the mulch has to be done in a very specific way might be a barrier to your trying out making a sheet mulched bed, so use what you have or what you can easily get.
- Grass clippings, non-animal food scraps, unfinished compost, leaves, and yard waste are all great materials. If you can get your hands on comfrey and dandelion leaves, add a layer of them, as they are both excellent bioaccumulators that concentrate nutrients from the soil in their leaves. They will release these nutrients back into your soil as they decompose.
- On top of this first deep layer, put on another layer composed of finished compost (complete with worms), decayed leaves, seaweed or rotted manure. This layer should be 3 to 5 inches deep.
- Finish with six inches of straw, wood chips, or sawdust. Do not bury the sawdust or wood chips. This top layer will prevent the mulch from blowing away and prevent weeds from growing.
- If you use wood chips, they should be small enough to decompose in a year or two. Another great topping, if you can get it, is animal bedding, especially from horse barns. This will break down quickly, and add both texture and nutrients to your soil.
Layering the New Sheet Mulched Bed
Planting Your New Bed
- Water the new bed regularly if the weather is dry. Some moisture is necessary for the layers to transform into compost. Overwinter a new sheet-mulched bed and it will be ready to plant in the spring.
- If you want to plant immediately, perennials or shrubs can be planted directly in the mulch, with some good topsoil added around them. Make soil pockets for annual starts or small seeds.
This video shows in detail how to sheet mulch. The product they are using, EcoCover, is made in New Zealand, from recycled paper from landfills, and is a much more eco-friendly product and cost-effective.than plastic mulch covers in large commercial gardens.
For our small garden beds, any newsprint paper or cardboard (corrugated is best, from discarded boxes) works just fine, and fits with the 3Rs: reduce, reuse, recycle.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2008 Nicolette Goff