Sheet Mulching at Bresnahan Elementary School

Nourishing the North Shore will be opening a new garden at Bresnahan Elementary School.  To prepare the garden space we used a technique called “sheet mulching."  This method suppresses weeds and builds fertile soil by adding thick layers of organic matter to the ground.

Some benefits of sheet mulching are:

1.     Weed suppression

2.     Better soil structure

3.     Adds nutrients to the soil

4.     Encourages earthworms and microbes (good for the soil!)

5.     Doesn’t require machinery

6.     Does not damage soil structure

7.     Does not damage life in the soil (earthworms, microbes)

How do you sheet mulch???

There are many ways to sheet mulch, some simple and some more elaborate.  At the Bresnahan school, we kept it nice and simple because we used the supplies that were readily available to us.  The key ingredients are: water, cardboard, organic matter.  Organic matter can be: compost, mulch, leaves, straw, kitchen scraps, grass clippings, etc.

Layer 1:  This is the very bottom layer touching the ground.  We spread a thin layer of moist compost over the existing grass.

Layer 2:  We covered the compost with large pieces of cardboard, placing the pieces so that there were no gaps in between.  When sheet mulching, you only want to use plain, uncolored cardboard.  And make sure there’s no tape on it, as it will not breakdown.

Layer 3: We spread weed-free salt hay over the cardboard so that it was a couple inches thick.  

Note: it also doesn't hurt if you have a cute doggie hangin' around!

Note: it also doesn't hurt if you have a cute doggie hangin' around!

Layer 4: For our final layer, we spread compost over the entire area.  We wanted this to be our thickest layer, it ended up being about 6 inches thick! 

We were very fortunate to have had all of this lovely compost donated by Mike Hatheway at Hatheway Landscape.  Thanks again Mike!!!

So how does it work???

 Sheet mulching is used to kill whatever weeds or grasses are underneath your layers of organic matter while building up the soil and creating an environment for healthy life in the soil.

What roles do the layers play?

Cardboard: is placed so that no light can get to the weeds underneath, therefor killing them.  It also acts as a food source for earthworms and microorganisms.

Straw:  acts as a mulch and another source of organic matter to be broken down.

Compost:  will contribute to the bulk of the finished soil and add essential nutrients to the soil.  Compost also contains beneficial microbes.

Water: the workers in the soil, earthworms and microorganisms, need moisture to survive.

Earthworms/Microorganisms: breakdown the organic matter and leave nutrient rich soil.

Tips:  Add water at each layer to ensure that the materials will retain moisture and so that they won't be blown by the wind.

This process is so easy and can be used on any backyard-sized area.  Give it a try!