Soil is the number one priority for the garden. It feeds and houses your plants, and provides them with the nutrients, minerals, and bacteria they need to produce fat, juicy vegetables and bright, vibrant flowers. The more work you put into creating good soil, the more impressive your garden each year.
The plants in your garden will take nutrients from the soil as they mature throughout the year. It’s your job each fall and winter to replenish the stocks and to add to the soil in order to provide enough food for the plants year after year.
Mulching is one way of keeping garden soil healthy, usually as part of a no-till style of gardening, where the soil isn’t tilled over before planting each spring and after harvest each fall. There are many practices that gardeners and farmers swear by, however. Others include tilling fertilizer, compost, and organic matter into the soil; amending the soil with compost tea from worm bins and compost piles; rotating crops every few years; resting the soil to give it time to renew itself naturally.
A lasagna mulch is created much like a lasagna you’d eat. You lay down layers of organic matter, and as the layers decay into each other, they leach nutrients like phosphorous, nitrogen, and potassium, the three main ingredients in fertilizers, as well as an array of other goodies, into your soil.
Start your lasagna mulch off with a manure, such as chicken or horse manure, available for sale at local nurseries as well as ranches and farms. Manure is rich in nutrients and minerals that make plants and soil communities thrive. If you choose, you can turn over any plants growing in the soil first, such as last year’s vegetable crop, or the lawn. Turning the soil is not necessary for a lasagna mulch – it’s personal preference.
After a 5-6 inch thick layer of manure, add a layer of cardboard or newspaper. This layer keeps out weeds and acts as a sponge to keep the soil moist. One layer of cardboard, 2-3 layers of paper bag, or 6-8 sheets of newspaper should do the trick. If you find weeds popping up in your bed, you may need to add more material to the mulch.
Depending on your zeal and energy, you may continue to manure and cardboard the plot as many times as you’d like. One is certainly enough, but two is good for a beginning plot, or very degraded soil. If nothing was growing on the soil before you mulched it, you may consider the soil desertified or dead, and add an extra round of manure for good measure.
On top of everything, add a thick layer of fall leaves, wood chips, nut shells, or store-bought mulch. The top mulch acts as a protective layer. It should be replenished as it decays, so there’ll always be a nice, thick pile of decaying organic matter on top of your soil.
You can leave the completed lasagna mulch as long as you’d like before planting. Overwinter the bed and plant in the spring or summer, cutting an ‘x’ through the cardboard and sowing directly into the lasagna layers. For particularly unhealthy or desertified soil, you can leave the mulch alone for a year, letting nature restore what was once a dead piece of ground.
A lasagna mulch is a low impact, low labor way to renew your garden soil and prepare it for the growing season, or to restore soil that’s lacking enough life to grow plants. Soil is an important resource for all living things, and we should care for it where we can.