Healthy, living soil is full of oxygen, water, and life to support your plants. This is the food your plants need to consume for good health. Creating healthy soil in layers is referred to as soil sheet mulching, or “soil lasagna.” It isn’t too much different than cooking a pan of lasagna in your kitchen.
Soil lasagna increases healthy microbes so much, they actually cook down the organic matter and start eating up old grass in your landscape as food.
All you need to do to encourage the active benefits of soil lasagna is keep it moist. The length of time for soil lasagna to provide the maximum benefits start to finish depends on the kind of grass you have.
Supply list to create your soil lasagna
- Shovels and rakes
- Bins to hold removed grass and soil
- Landscape flags
- Painters’ paper or large cardboard sheets
- Compost, worm castings, or compost tea
- Hose with a shutoff nozzle
NOTE: Consider first whether you need any digging permits. If yes or you aren’t sure, call DIG ALERT (8-1-1 or 800-422-4133) two days in advance. Check with your local water agency for any local water use restrictions.
Once you have checked for permits and any water use restrictions and remove your lawn, you’re ready to get started. Remember, use healthy removal methods to set your landscaping up for success. Expect to remove and haul away about six inches deep of grass and soil. Rent and fill a dumpster which can be picked up and disposed of responsibly later.
Dig a trench eight to 12 inches deep, about one shovel depth, and at least 12 to 24 inches wide around any hard surfaces and building foundations. You need to complete contouring for rainwater absorption and retention and any other work to hardscaping such as moving or installing patios, paths, and other features.
Use the landscape flags to mark sprinkler heads so you can find and adjust them later.
Layers supply the magic
Add an inch deep layer of compost on top of the graded soil. You can also use humates, a freeze-dried compost available at specialty landscaping stores, or spray with compost or worm tea. You are adding an instant food sources and additional microbes to the soil.
Water thoroughly. Roll out your painters’ paper or cardboard. Overlap at the seams about six inches and be sure all of the soil is covered. At the hardscape borders, make a burrito of rolled paper and mulch to prevent grass from resprouting.
Water the paper, and then add another layer of compost if you wish. Rake a thick, six-inch larger of mulch over the paper and compost. Now it should seem obvious why this is called a Soil Lasagna.
Water again thoroughly. The mulch will absorb a lot of water before it becomes thoroughly soaked through.
When you are ready to plant, you can dig a hole right into it, cutting through any paper or cardboard that might still be there, planting into the delicious and healthy soil below. Allow as much time as you can so your soil develops more healthy microbes for your new plants. But you can plant right away if all grass has been removed and you’re short on time.
This article is part of a year-long series inspired by the 71-page Sustainable Landscapes Program guidebook. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.