Editor’s note: This is the first in a two-part series about replacing a lawn with lower- water alternatives.
The amount of water needed to maintain a Kentucky bluegrass lawn in Colorado (and the associated cost) is enough to give any homeowner pause — and might cause many to reimagine their landscape with a smaller lawn, or no lawn at all. If you are thinking about renovating your landscape, the first step is to remove the lawn.
Solarization and sheet mulching are two natural methods for removing your lawn. Solarization uses the sun’s radiation to kill the grass, along with common annual weeds, harmful soil microbes and seeds down to a depth of 4-12 inches. Covering lawn to be removed with clear plastic tarps (2-4 mils thick) result in the tarps trapping heat and moisture, encouraging seed germination and plant growth. Over four to six weeks, the tarps will block access to water and heat up the soil to the extent that the vegetation underneath the tarp will eventually die. This method requires six hours a day of full summer sun.
To kill grass using the solarization method, first saturate the lawn and soil to a depth of 12 inches. Lay one tarp directly over the soil surface, then add another tarp to cover the affected area. This will create an air space above the first layer of plastic, which will increase the temperature underneath the tarps, resulting in a quicker and more effective killing of the lawn. Finally, secure the edges of the tarps with landscape staples, bricks or sandbags to prevent the tarps from blowing away.
Another method for removing a lawn is sheet mulching, which works by starving the grass of light and water. This method takes six to 10 months, and can be started at any time of year, providing that at least three months of growing season are included in that time frame. For example, if you installed sheet mulch in August, the grass would die during the growing season and throughout the winter, allowing you to plant the area in the spring.
To get started with sheet mulching, first mow the grass at the lowest blade setting. After mowing, cover the target area of grass with cardboard (flattened boxes or purchased rolls) or newspaper (10-12 layers), making sure to overlap the edges to prevent weeds. Finally, cover the cardboard or newspaper with 4-6 inches of wood mulch. The sheet mulch is left in place permanently, but over time, the dead grass, sheeting, and mulch will decompose into organic matter that will enrich the soil.
Whichever method you choose to remove your grass, remember that it is important to kill the grass completely; otherwise, the grass may regrow among your new plantings and create unwanted landscape maintenance issues.
Next week: Alternative landscapes to a lawn.
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