CARDBOARD IS EASILY found at fast food restaurants, supermarkets, and from boxes sent by nearly any online store.
We are surrounded by corrugated cardboard that’s used for transport packaging, food packaging, and decorative boxing.
Sadly, the currently recycling rate for paper and board packing waste is only 49 percent, according to a Green Industries study on food packaging wastes and environmental impacts.
That means that 51 percent of cardboard products are not recycled. What happens to that wasted cardboard?
Typically, it is thrown into landfills or burned, which are not environmentally sustainable practices.
Utilizing cardboard as a mulch is a sustainable and creative way to hack your cardboard; It keeps the cardboard out of the landfill while functioning as a mulch and weed block for your garden.
Most importantly, it can be an important component of sheet mulching also known as “lasagna gardening”which is an easy way to build a no-dig garden that does not require tilling.
Using this technique, which was originally popularized in the late 1990s by Patricia Lanza’s creative book, Lasagna Gardening, can help you build a rich soil within a few short seasons.
HOW TO SHEET MULCH
1. In the late Fall, mow or cut your vegetation to the ground.
2. Cover your garden area with a thick layer of flattened cardboard boxes. (Be sure to remove any staples or tape)
3. Overlap the cardboard by at least six inches.
4. Spread a layer of wood chips on top of the cardboard (between 2-8 inches)
HOW TO SHEET MULCH TO CREATE A BASE FOR PLANTING BEDS
5. Add a 2 inch layer of dried grass clippings mixed with food compost, or a thick layer of fall leaves
6. Cover the garden area with a thick layer of newspaper and water it well.
7. Add a 2 inch layer of compost including coffee grounds.
8. Add a 2 inch layer of aged manure.
9. Top off the layers with a heavy layer of compost.
10. Wait patiently until Spring, then dig planting holes directly through the layers and plant the garden.
11. Mulch around the plants to help keep weeds down and moisture at the roots of the plants.
12. Once a sheet mulch garden is established, place cardboard around the plants before covering with compost and wood chips. 
Planting cardboard as the first layer of your sheet mulched garden helps kill the grass and weeds beneath. Once a sheet mulch garden is established, place cardboard around the plants before covering with compost and wood chips.