Lasagna Mulch (aka Sheet Composting)

(By Gina Gervase, Communications Assistant)

Maybe your traditional lasagna recipe doesn’t call for coffee grounds, blood meal, sawdust, or pine needles, but we promise our recipe for “lasagna” mulch will make your garden very happy. Similar to the layering of noodles, sauce, vegetables, and cheese, lasagna mulching is built with layers of soil nutrients.

(Illustration by Gina Gervase)

The mulch disperses these nutrients slowly into your garden soil, which in turn encourages earthworms to take up residence. The trails they create underground aerate the soil, further improving soil tilth. Mulch above ground helps the soil retain its moisture, and its insulating quality keeps soil cooler in the summer and warmer in the winter. Above ground, mulch means less watering as well as less weeding. You can eliminate your use of herbicides as mulch makes it difficult for weeds to take root.

The most effective mulch calls for the right preparation. In the area you want to mulch, be sure to cut vegetation as low as possible. Removing stubborn weeds now will save you the labor of weeding them later. Loosening the area with a spading fork will help improve drainage and aerate the soil.

Once your area is prepped, you can start with the layers. Cover your chosen area with four to six layers of newspapers. Newspapers are an excellent source of carbon (an important garden nutrient) and help smother any germinating weeds. Wet the newspapers to speed along their decomposition process.

Atop the newspaper, cover with an inch thick layer of a nitrogen source. Nitrogen is essential to a plant’s photosynthesis process, converting sunlight to energy, and is a building block of plant growth. Nitrogen sources commonly found in your garden include: coffee grounds, kitchen scraps and grass clippings. You can also use composted manure, alfalfa pellets, cottonseed, soybean or blood meal.

After you have laid your nitrogen layer, top it with an inch thick layer from a carbon source. Leaves, pine needles, corn stalks and peat moss are all excellent sources of carbon, along with sawdust, newspaper, cardboard and hay.

If you are mulching your garden in spring or summer, you can cover the top of your carbon layer with burlap and secure the edges of the material with heavy weighted items likes rocks to keep all the ingredients in.

If you are mulching in winter, you can build up thicker mulch by alternating inch thick layers of nitrogen and carbon. Just be sure make your last layer a carbon source to discourage flies from laying their eggs in your nitrogen-filled kitchen scraps.

A slow cooked meal for your garden, your lasagna mulch will be done when the mulch is fully decomposed so that it appears and feels like earth. You can then plant directly into the mulch. If you're itching to plant right away, top with a few inches of compost and plant directly into that!

Happy mulching!

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