Using Cardboard to Build Healthy Soil

I recently read an article about using cardboard to build healthy soil and help mitigate climate change. In healthy soil, gardeners and small-scale farmers can sequester as much as two tons of carbon per acre, which could significantly reduce the emission of greenhouse gases. According to Dr. Rattan Lal of Ohio State University, “a mere 2% increase in the carbon content of the planet’s soils could offset 100% of all greenhouse gas emissions going into the atmosphere.” As we know, healthy soil also means better gardens that support a diverse ecosystem; conserve water; grow plants more resistant to pests and diseases; and reduce the amount of labor required.

Using three different methods, it is possible to avoid a lot of weeding and disturbance of the soil layers when planting, whether ornamentals or vegetables. This method builds the soil because worms eat the cardboard, multiply, leave their carbon rich castings and aerate the soil. Over time, this results in dark fluffy soil full of organic matter.

When using cardboard, here’s what to do.  For large seedlings or plants, place sheets of cardboard directly on weedy ground, then dig holes about a foot in diameter where you want your plants. Fill the holes with compost, plant your plants, press them in firmly, water well and cover the cardboard with mulch if desired (not necessary for vegetables). For smaller plants, spread compost directly on untilled ground, lay cardboard over it, soak it with water until it softens and then cover it with well-aged wood chip or other mulch. Stab holes in the cardboard with a dibble, small trowel or bulb planter and plant your plants in the holes. For sowing seeds, make sure the ground is moist. Place cardboard directly on the untilled ground, wet the cardboard and cover it with compost. Sow or scatter your seeds and water.

Why not give this a try? I know many of you have used cardboard or thick layers of newspaper to smother weeds and eliminate invasive plants, but how easy to just plant right through it all? I’m going to try this myself next year in an area of grass I want to turn into a native perennial garden. If you do try this method, let me know how you do.

Editor’s note: Here are 2 helpful videos on employing versions of this process.  Replacing Your Lawn with Sheet Mulching (https://youtu.be/kuw40hHCqTA) and Sheet Mulching a Garden Bed (photo credit – https://youtu.be/oURszYpF2WA). These videos were not produced by the JCCWMGA. They are used for informational purposes only and are not an endorsement.