Marin Master Gardeners
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Marin Master Gardeners

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Gardening Tips - Lasagna Compost

Fresh compost
Fall is a fabulous time to cook up some comfort food favorites like rich multi-layered lasagna, loaded with nutritious veggies, protein and calcium. But why limit your cooking to the kitchen? Using the same technique of layering various colors and textures, and allowing them a lengthy cooking time to meld together, also works in the garden. The result will be luscious weed free soil, alive with micronutrients to encourage vigorous plant growth.

Lasagna composting, also known as sheet composting or sheet mulching, is an easy way to grow your soil, attract beneficial bacteria and our best friends, the earthworms, to your garden plot.

Cindy LaMar recently shared her sheet compost trial garden with our fellow Marin Master Gardeners. Cindy’s guide was Gaia’s Garden by Toby Hemenway. In the chapter “Bringing your Soil to Life” she found detailed instructions for sheet mulching. The results are truly amazing and inspirational.

A simple recipe for lasagna composting

Ingredients:

  • A selection of greens (materials high in nitrogen) such as fruit and vegetable peelings, egg shells, tea bags, coffee grounds, fresh lawn clippings. Animal manure (a green, as it is very high in nitrogen).
  • A selection of browns (materials high in carbon), such as dried-out leaves, straw, wood shavings, pine needles, nut shells.
  • Newspaper and/or corrugated cardboard (a brown)
  • Organic compost and soil

1. Assemble all of your ingredients in easy reach before you begin.

2. Prepare your leave-in-place container by outlining with stones (as Cindy did) or use a trowel to carve an outline in the earth.

3. Layer the materials and water each layer well before adding the next.

4. Cook for 4 to 6 months, or longer.

5. Allow to cool before planting directly into the compost.

Cindy found an economical way to gather her supplies. First she visited an appliance store where they were happy to give her large, heavy duty cardboard boxes. The manure was free at the Miwok Stables. Her purchases were limited to straw and compost. Around Halloween many people have straw for parties, so you might be able to pick up a bale for free after an event.

Remember to check for two things: you want straw, not hay. Hay includes seeds and you could end up growing way more problems than you are solving! Straw is just the stems from grain plants. Also, inquire if the bale has been sprayed with a fire-retardant. You would not want that in your soil.

After you have gathered all of your supplies, plan to work on a wind free day to insure your ingredients don’t blow away as you are layering. Have a water hose handy to thoroughly wet down the layers as you add them. Cardboard can absorb an amazing amount of moisture, so wet it thoroughly before moving on to the next layer.

The cardboard layer effectively shuts out all the sunlight to the vegetation below, stifling its growth. The manure heats up the pile and effectively “cooks” most weed seeds. Earthworms are attracted to the manure and work their magic by aerating the soil in their travels and leaving behind their nutrient rich castings. The straw further smothers weeds and rots into rich compost.

Your cookbook collection probably contains dozens of delicious recipes for that perfect lasagna casserole, each of them just a tad different from the other, but all using a layering technique. So too will each lasagna compost vary. Ingredients will differ one from the next, but the basic technique will remain the same.

Perhaps you are already thinking, “Manure! How will I ever get that smelly stuff home?” Not to worry; well rotted manure is readily available in bags at your local nursery center. Rotted manure will not heat the compost as intensely as the fresh product, but that’s okay.

Newspapers are a fine substitute for the cardboard. Just use lots of it to build a ¼- to ½-inch layer. Don’t use the slick glossy sections as they may contain metal pigments.

Organic compost is readily available in bags if you do not have the homemade product to use. A layer of your own good garden soil can also be tossed in. Stop by Starbucks for a bag of their complimentary coffee grounds to add to a layer.

Though the miraculous powers of straw have been well documented (have you read The Ruth Stout No-Work Garden Book?), if you just can’t bring yourself to put a bale in the trunk of the family sedan, the top layer can be any of the other browns: bark, dried leaves, pine needles, etc. Just be sure to end with a layer at least 2 inches thick.

Start your lasagna composting soon to take advantage of the upcoming rains and you will be ready to plant in humus rich earth next spring! Bacteria, fungi, and other microorganisms will thrive and enrich your soil to better feed your plants. The thick layer of mulch will discourage weeds and you will be rewarded with abundant growth!


By Jane Scurich

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