Lasagna Gardening Is an Easy, Low-Effort Way to Create Compost—Here's How to Do It

Lasagna gardening may sound like the most delicious pastime, but it doesn't actually refer to growing the tomatoes, herbs, and wheat that you could turn into the classic tiered pasta. Instead, it's another term for sheet composting, a technique in which layered materials add nitrogen and carbon to your soil as they decompose, creating a self-sustaining cold compost pile that you can sow seeds (or transplant starts) into directly.

The process has environmental benefits that mirror other types of composting—like reducing your waste stream as you add food scraps and cardboard to your garden instead of your trash can and helping you grow a thriving backyard garden that reduces your dependence on commercial food production. But it also requires less effort than other types of composting, says Dave Kayfes, a master gardener and compost specialist with the Oregon State University Extension Service. Sheet composting doesn't require any turning; it works with varying ratios of nitrogen to carbon; it leaves microbes alone to break down the materials; and it leaves you with a no-till patch that's ready for planting. Ahead, we talked to Kayfes to learn more about this easy, beneficial gardening practice.

How to Build a Lasagna Garden

A single layer of cardboard or mulch can offer a small-scale version of lasagna gardening, suppressing weeds and preserving the moisture within the soil. But building a deeper pile with multiple layers of nitrogen and carbon allows you to build a self-composting bed anywhere in your yard.

Choose Your Location

While you can use the technique in a raised garden or an already-defined bed, Kayfes says lasagna gardening works best on a lawn or weed-filled area that you hope to turn into a growing space. "That's where it really becomes beneficial because you're keeping down the weeds and building up the microbes and nutrients into the soil you have underneath there," he says. In his experience, the technique works just as well in sunny spots as it does in shady spots. And drainage doesn't change the process, either, so opt for a location that is easy to access and offers the best growing conditions for your plants.

Materials Needed

Sheet composting requires two types of materials: those that break down to provide nitrogen and those that decompose to produce carbon. You can mix multiple types of materials into a single layer as long as they all produce either nitrogen or carbon. Kayfes says his go-to items are coffee grounds (which he picks up in bulk from a local grocery store) and vegetable waste for nitrogen, with cardboard for carbon. Here are other materials to use:

Nitrogen sources:

• Used coffee grounds
• Composted manures
• Alfalfa pellets
• Fresh weeds
• Vegetable scraps
• Fresh grass clippings
• Cottonseed meal
• Soybean meal/blood meal

Carbon sources:

• Sawdust
• Leaves
• Cornstalks
• Pine needles
• Peat moss
• Newspaper/cardboard
• Straw/hay
• Wood chips
  

Instructions

1. Prepare your composting area by digging out the sod, grass, and weeds in your future planting space.
2. Place your first layer (which should be cardboard, newspapers, or another carbon source) on top of the soil; you can also start by layering directly onto the existing ground after mowing.
3. Wet the layer of carbon and top it with a layer of nitrogen—like grass clippings, coffee grounds, weeds, or vegetable waste.
4. Alternate layers of carbon and nitrogen until your garden reaches the depth you want. The typical depth is 18 to 36 inches, but you can adjust the thickness of each layer and the total height according to your space and the materials you have, says Kayfes.
5. Finish with a carbon layer, like dried leaves or straw, to prevent food scraps in your nitrogen layer from attracting flies or insects.

Planting Your Lasagna Garden

Sheet composting is a form of cold composting. Without turning the pile and adjusting the nitrogen ratio, you're preventing the layers from heating up. This means it takes longer for the materials in the pile to decompose—often six months or longer.

A pile built toward the end of the summer and into early fall is often ready for planting in the spring; if the layers "look and smell like fresh earth," you can bury seeds or transplant young plants using the same method you would in any other garden. The layers will have decomposed, creating a rich mixture of carbon and nitrogen to give your plants a boost of energy and nutrients.

How to Maintain Your Lasagna Garden

While hot compost piles require a stronger nitrogen content to produce the heat that causes faster decomposition, lasagna garden ratios are less strict—and can be designed to accommodate the type of plants you're growing. "Either way, whether you're three-to-one nitrogen or three-to-one carbon, you still get a good pile," says Kayfes. "With high nitrogen, it's better for vegetables; with high carbon, it's better for bushes and trees."

At the end of the growing season, Kayfes recommends cleaning out the garden, using the remaining plants as a nitrogen layer, and adding a layer of dry leaves on top. "The last layer is an insulation that protects the biology that's going on," he says. "Having the top layer of leaves protects you from that extreme weather and allows the activity of the microbes to work even in winter. Then in March or April, you don't have to dig, you don't have to cultivate—you just scrape off the leaf layer and plant right into it."