April 19, 2010
by: staff writer
Are you searching for a way to suppress Oxalis or similar perennial weeds without the application of herbicides or weeding by hand? Then you may want to explore a method known as sheet mulching or layered composting. Sheet mulching is simple, safe and friendly to our environment, as it involves recycling old newspapers, paper bags or pieces of cardboard to control weeds while adding valuable nutrients to the underlying soil. Sheet mulching is also utilized by organic gardeners and those subscribing to the Permaculture approach of repairing and balancing our Earths' ecosystem.
To begin with sheet mulching, e.g., in your vegetable garden or in any landscaped area, simply cut the perennial weed growth, leaving the clippings where they fall or if the growth is not overly established, simply smash-down the weeds. If within your budget, you may spread a thin layer of organic compost over the green growth and moisten with water. This will assist the decomposition process.
In the photo to the right, you can see that the perennial weeds have already
been trimmed (in this case, hoed-down) and left lying on top of the soil - as suggested above. This will provide organic matter for the decomposition process as well.
Meanwhile, be sure and soak your newspapers, cardboard bags or pieces of cardboard box in water to initiate the decomposition process. Begin spreading the newspaper (8-10 sheets thick) or cardboard over the weeds, overlapping by approximately one third or so.
If necessary, you can weight down the edges with some soil or rocks. The newspaper, cardboard pieces or paper bags, serve to not only to suppress the perennial growth, but to creates a natural moisture barrier, assisting the underlying soil to retain its moisture and providing a haven for natural and beneficial bacteria and organisms to form.
In this case, both newspappers and cardboard boxes were utilized for the sheeting material.
Next, you will want to place a layer of straw or some other form of mulch on top of the newspaper or cardboard you placed in the previous step. Newspapers usually possess a good deal of carbon, so you may want balance this with Lucerne (Alfalfa hay as seen in the photo to the right) or pea straw (which are both very rich in nitrogen) if there is not an abundant amount underlying perennial growth to start. Wood chips or leaf waste (the kind your local tree trimmers generate) are also a viable substitute.
Be sure to create a layer of mulch that is 2"-6" thick. At this point, you may plant directly into your sheet-mulched area by poking a hole into the cardboard and digging an appropriately-sized hole for your plant or tree. Add a bit of native soil and organic compost at the proper amendment ratio. Just be sure to keep the root crown clear of soil and mulch.
In time, the newspaper, cardboard, etc. will begin to decay and break-down, while attracting earthworms and provide a nutrient-rich treat for your soil! And, the process may be
repeated as often as necessary. Give it a try!