Simple Sheet Mulch

Mulch helps conserve water, calms temperature swings, and improves soil. Sheet mulching is one of the gardener's most powerful tools. It builds soil and eradicates weeds without power equipment or chemicals.

Sheet mulch is beautifully simple. It begins with a weed barrier next to the soil, such as cardboard or newspaper. You can also use cloth, but it obviously takes longer to break down. I prefer cardboard because it is so much easier and faster to cover large areas. And I purchase a lot of things online, so it's an easy way to use all the boxes! (As a side note, I read that the ink in glossy newspaper contains metal pigments, but the black and white ink is soy-based and nontoxic; I assume cardboard is the same.)

If you wish to use soil amendments, such as lime for acidic soil, put them down first. You can also add some high-nitrogen material, such as fresh cut grass or produce waste from the kitchen. (For my ultra-simple sheet mulch in this area, I did neither of these.) Then add the weed barrier. This layer needs to block light in order to kill the existing plants; make sure the cardboard or newspaper overlaps so no light peeks through. It's a good idea to hose down the layer as you go so your paper doesn't blow away.

 A thin nitrogen-rich layer should be added next. Then comes the bulk of the sheet mulch: ideally, about a foot of organic matter such as straw, hay, leaves, wood shavings, etc. For my simple version, I put down only a few inches of straw. If you are using a high carbon mulch, you may add some nitrogen to this layer so the mulch decomposes more quickly. Again, it is beneficial for the mulch to be moistened.

On top of this, add a couple inches of compost. If the new bed won't be planted for several months, throw on some kitchen waste and treat this space as a compost pile.

The final layer is a couple inches of weed-seed-free material such as straw. I wouldn't recommend using hay for this top layer, as the dormant seeds will germinate and cause lots of unnecessary weed-pulling. I used wood chip mulch for my top layer. My goal was to keep the straw in place and give a finished look to the space.

I plan to plant this space next spring when the cardboard is well-rotted and easy to put a shovel through. A newly-constructed sheet mulch bed can be planted immediately, however. Sheet mulching is also known as lasagna gardening. Here is an excellent article with growing information for specific plants.

http://www.motherearthnews.com/organic-gardening/lasagna-gardening-zmaz99amztak.aspx?page=8#axzz2N4iMBChZ