At the BELL Garden we try to promote gardening tactics that are accessible to the home gardener and reduce their workload while building fertility. Lasagna gardening (or sheet composting) is one method of bed preparation that is easy, effective and sustainable. It can be practiced just about anywhere and it requires materials that are mostly free or would typically be thrown out.

Lasagna gardening is typically used to make raised beds, but you can follow the basic principles to suit your needs. At the end we will show an example of how we used these principles to make some of our flower beds.

How it Works

As the name suggests, lasagna gardening involves layering different materials until you reach your desired bed depth. It works by following basic principles of composting to create compost like conditions in the garden bed. A wide variety of materials can be used as long as you know the difference between your “greens” (nitrogen source) and “browns” (carbon source).

Green materials include anything that is leafy and green, like grass clippings or pulled weeds (watch out for seed heads). They also include kitchen scraps, coffee grounds, or just about anything you would throw in your home compost bin. The defining characteristic of “green” materials is nitrogen which is the main element plants use to become green and leafy.

Brown materials include things like fallen leaves and twigs, shredded paper, cardboard or last years flower stalks. The defining characteristic of brown materials is carbon. Carbon is an important soil element because it helps bind nutrients to soil, improving long term fertility.

How to Make it

Lasagna gardening is typically a technique used for filling raised beds to a depth of 18-32″. So if you don’t have a raised bed that needs to be filled you may have to bend the rules to suit your needs.

First step is to clear the area of any weeds. This can be as simple as buzzing them to the ground with a weed wacker or lawnmower. It is not important that the area is completely clear because the next step is to lay cardboard. This creates a biodegradable barrier that blocks the existing weeds from returning.

After you have laid the cardboard, you can begin layering your different materials, starting with your browns and then the greens. Repeat this until your bed is 18-32″ deep.

Finally, add a 4″ layer of compost or garden soil to the top. Your lasagna bed is finished and is ready for plants!

Our Modified Lasagna Beds

We recently made some lasagna beds at the BELL, but we made some changes to suit our needs.

We lined our beds with stone so we only had 6″ of depth to layer. Our layers were as follows:

  1. Cardboard
  2. Oak leaves
  3. Regular dirt (typically not the best choice but we had some that needed to be used.)
  4. Mushroom compost (we think the nutrients in the compost will counteract the inertness of the dirt.)

In the first year, we expect to get okay results. The real benefits of lasagna gardening come once the materials in the pile begin to break down. Eventually the oak leaves will decompose into a rich black humus, and the plant roots will penetrate the cardboard.

Because we covered the ground with cardboard and filled the bed with fresh material, these beds should be weed free for awhile, giving us time to focus on everything else in the garden!

We hope you’ll give lasagna gardening a try!

Starting with bare space.

Setting stones to mark our beds. We made a shallow trench to set the stones.

Laying cardboard. Good sources for free cardboard include appliance and mattress stores. Make sure it is not glossy, or waxed and be sure to remove all plastic labels and tape.

Adding the dirt layer. This is normally not something any gardener would recommend but we had extra that needed a home.