Lasagna Compost

What is lasagna compost?

Lasagna compost is a great method for turning a lawn or weedy space into a new garden bed. This method kills the underlying plants by starving them of light, while providing a fertility boost to the soil.

• If the area is weedy, start by cutting the weeds down. If the cut weeds do not have mature seeds, they can be left on the ground to decompose.
• Next, lay down a barrier layer of newspaper (several sheets thick) or cardboard that covers the area without gaps or cracks
• Lay down a 1-2" layer of green material* (kitchen waste, green plants, or grass clippings) on top of the barrier layer.
• Lay down a 2-3" layer of brown material** (dead leaves, dead plants, woodchips, or shredded paper products) on top of the greens.
• Sprinkle a thin layer of soil or finished compost over the browns.
• Continue adding layers of green material, brown material, and soil or finished compost until the layer is 12-24" thick. (Ideally this should be done all at once or within a few days.) Add enough water to dampen the layers all the way through.
• To maintain: Keep the layers from drying out by adding water as necessary.

Depending on particle size and specific materials used, the lasagna compost should be ready to plant into after 3-6 months. Lasagna compost is often assembled in the late summer or fall and left to break down until the following spring.

What composting style does it fit?

Lasagna compost takes little work after assembling, so it fits well with both hands-off and hands-on composters. It is most useful to people who want to create more garden space.

What space does it need?

Lasagna compost can be assembled on top of grass, weeds, or barren soil to create a new garden plot. It works best in full sun or partial shade.

How does it work?

Lasagna compost is a form of aerated composting which relies on naturally-present decomposition microbes to digest organic waste and turn it into finished compost. These microbes require 5 things to function properly:

• Green material* (this should be about 40% of the mix)
• Brown material** (this should be about 60% of the mix)
• Moisture
• Oxygen (air)
• A small amount of soil or finished compost

*Green materials are nitrogen-rich, fresh stuff such as green plants, grass clippings, and kitchen waste. Kitchen waste here includes vegetables and fruits, tea bags, coffee grounds and filters, egg shells, and grain-based products but excludes meat, bones, dairy, and grease.

**Brown materials are carbon-rich, weathered stuff such as dead leaves, dead plants, sticks, woodchips, and shredded paper products.

If the compost doesn't seem to be breaking down, check that it is still damp all the way through. Add water if necessary. If it is damp and still not breaking down, consider adding additional green materials* to the mix.

If the compost has a putrid smell, fluff it to add air and stir in additional brown materials.** Small amounts of soil can also be added.

Can you use it all year?

Although decomposition will stop in winter, lasagna composts can be added to all year long. However you should stop adding new organic waste in the summer or early fall if you want to plant into the lasagna compost the following spring. At that point a different method should be used to divert organic waste.

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Got more composting questions? Email the Composting Hotline at [email protected] or leave a message at (306) 931-3249.

Residents of Saskatoon can also use the hotline to request a free home visit from a Compost Coach. Our Coaches can provide composting advice, help you set up a new compost system, or troubleshoot and existing system. Visits typically take 15-45 minutes.