How To Improve the Soil in Your Garden With Sheet Mulching

book on how to grow perennial vegetables

Perennial Vegetables: From Artichokes to Zuiki Taro, a Gardener's Guide to Over 100 Delicious, Easy-to-Grow Edibles

  • Is your garden typically riddled with weeds by mid-summer?
  • Are you looking for an organic method for improving the fertility of your soil?
  • Interested in learning inexpensive techniques for maximizing your garden’s water retaining properties?

Master organic gardener Eric Toensmeier, author of Perennial Vegetables and coauthor of Edible Forest Gardens, has the perfect solution for you: sheet mulching! Sheet mulching combines soil improvement, weed removal, and long-term mulching in one fell swoop. This technique, also known as lasagna gardening, builds organic material and smothers weeds at the same time, so they never get a chance to grow!.

Nine Simple Steps to Sheet Mulching,
adapted from Eric Toensmeier’s Perennial Vegetables

  1. Mow or cut your lawn, weeds, or other vegetation right down to the ground.
  2. Plant any crops that will require a large planting hole (including woody plants, perennials in large pots, and large transplants).
  3. Add soil amendments (as determined by your soil test).
  4. Water the whole area thoroughly. You are going to be putting a layer of cardboard or newspaper over it, and rain and irrigation won’t soak through very well until that weed barrier breaks down. Water also helps the decomposition process get going.
  5. If you have compost materials that may contain weed seeds (like fresh manure, leaves, or hay), spread them in layers on the ground. Put a dry, carbonaceous layer of hay or shredded leaves below any manure layer. Avoid thick layers, and make sure to get a good carbon-to-nitrogen ratio just as if you were building a compost pile. Water this layer well.
  6. Lay down a weed barrier. Large sheets of cardboard from appliance stores are recommended, because these last longer and are quicker to lie down. You can use layers of wet newspaper too. Make sure to have a 4- to 6-inch overlap where sheets meet so buried weeds can’t find a route to the surface. If you have already planted crops, or have other preexisting plants, don’t mulch over them. Cut holes in the cardboard to make some breathing space for each plant (or leave some room around each plant when laying newspaper).
  7. Now you can add your weed-free organic materials. Keep it simple, and just add a nice layer of compost. You can also do some sheet composting here, alternating layers of nitrogen-rich materials like fresh grass clippings with carbonaceous materials like weed-free straw.
  8. Add your final top mulch layer, at least 3 inches thick. Water the whole bed thoroughly once again. Your sheet mulch bed is complete.
  9. You can plant right into your bed if you like. To plant tubers or potted plants, just pull back the top layers until you get to the weed barrier. Cut an X in the cardboard or newspaper. If you are transplanting a large plant, peel back the corners of the X. Throw a double handful of compost in the planting hole and then put in the plant. Pull the layers and top mulch back around the plant, water well, and you’re all set. Planting seeds is easy too. Just pull back the top mulch to the compost layer and plant your seeds. You may want to cut through the weed barrier below first, depending on weed pressure below the barrier. If you are planting seeds, be sure to water regularly, as compost on top of cardboard can dry out quickly.

To learn more, see Perennial Vegetables by Eric Toensmeier (Chelsea Green Publishing).

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