Cardboard is an amazingly useful thing in the garden. Warren has written before over at TreeHugger about creating a no-dig garden using cardboard, and I've also tried my hand at clearing old weeds with cardboard boxes. But while I was watching a video of my old friend Mike Feingold's permaculture allotment, I learned that he incorporates a cardboard mulch into his regular crop rotation. So that's what I'm going to try this year, simply placing a layer of cardboard over the soil and planting through it with garlic and onions. (I just punch a hole through with a trowel and push the bulb in.) I then place a layer of earth, compost or leaf mold over the top to hold it down.
The idea is that cardboard acts as a permeable mulch - allowing water through to the soil, but preventing perennial and annual weeds from sprouting, hopefully stopping weed problems from building up over time without the need for digging. The mulch should also prevent excessive evaporation, and slow down any soil erosion. Add to that the fact that cardboard provides much needed organic matter as it rots down, and it also contains air spaces that help feed microorganisms in the soil, and it seems like an all-round win-win situation.
This final benefit is a little more speculative, but I've also noticed that cardboard left on the ground becomes a perfect habitat for fungi, which seem to love moving along the corrugated ridges. I'd postulate that a regular addition of cardboard may encourage mychorrizal fungi which are known to form beneficial relationships with a wide variety of plants.
And for those who argue that recycling or reusing cardboard boxes is a greener alternative, I'd note that I live in the country and have to cart my recycling on a good 15 mile round-trip. While I try to combine trips wherever possible, I'm pretty sure that finding a useful, zero energy, close-to-home use for my waste products is going to beat recycling any day. And as part of my philosophy of making gardening easy, if it allows me to grow more food with less effort, then I for one am convinced it's a winner.
Need proof that it's possible to balance being green and still be a supportive partner and parent? See how Ed Begley, Jr. does it on Planet Green TV's Living with Ed.