Saturday, April 27, 2013

Sheet mulching - not 900-count, 900 square feet

Sheet mulching, otherwise known as lasagna gardening, is an organic practice of putting down layers of alternating carbon-rich in nitrogen-rich materials to accomplish a number of goals.

The first is to kill the grass. I know, lots of people worked their entire lives to get the perfect lawn, but the last thing I want to do with my life is mow it -- I'd rather kill the grass and plant something productive in that open space.

The second thing sheet mulching does is brings in a lot of organic matter to enrich the soil. Organic matter can be anything, leaves, manure, hay or straw, wood chips, compost, even on garden debris from last year. The trick to a successful sheet mulch is getting the carbon and nitrogen ratios right so you don't have an imbalance. Too much carbon and there isn't any organic activity; too much nitrogen and it gets smelly.

There are books describing the perfect sheet mulch project, so I'm not going to go into it here. (I'm reading Gaia's Garden right now, great book!) The sheet mulch layers we're going to use to smother the grass and create lovely soil for our orchard will look like the following. From the surface down:
  • Woodchip paths or a 2" layer of compost seeded with a low-growing white clover
  • 6 to 8 inches of marsh hay (doesn't contain weed seeds)
  • 1 inch compost
  • solid layer of cardboard
  • 1 inch compost
  • coffee grounds
  • dead grass (leftover from the lawn)
  • original soil
Many people who sheet mulch their yards spend a lot of time collecting compost, old hay, leaves, cardboard, wood chips etc. But since we didn't have much time before we wanted to plant our orchard, we're purchasing most of the woodchips, compost and hay; and we scrounged cardboard from the neighborhood and collected coffee grounds from local cafés.

I will take lots of pictures during the sheet mulch process and show you how it turned out in a future post.
Two juniper trees were removed this week. Props to Garret of Gere Tree Care for the short-notice job.

Garret left a load of wood chips (some from the branches of our tree, some from earlier jobs). The tarp is less to keep them dry and more to say "Not free for the taking."