Lasagna Gardening, Done right, works beautifully!
Just built lasagna bed May2010
I'm an experienced gardener. I was quite skeptical of the lasagna method of building beds myself, but perhaps that also led me to put some care and attention into doing it right.
When you look at natural systems, they are constantly being replenished by leaf litter, dead bug and worm bodies and so on. This stuff doesn't get tilled in, it gets gradually incorporated by worms, bugs and micro-organisms. The roots of many annual plants, like our garden vegetables, don't penetrate more than a couple inches into the top layer of soil. It's been going on long enough I wouldn't call it a fad.
The least-decomposed green plant material, coffee grounds, old manure, woodchips and some vegetable scraps went into the bottom layers over a base of wet cardboard. Next layers were 3-4" of last-year's leaves, fresh grass clippings from a no-chem lawn, 5-6" of organic straw, with 1" layers of mature compost and topsoil between them. (Mostly free materials.)
It sure beat paying for, lugging and tilling many cubic yards of “topsoil” from sources unknown!!! As they like to say: “Your mileage may vary.” No method of gardening is going to be fool-proof. There are no shortcuts past education and experience. That given, I have found lasagna gardening to be a very viable method of building soil and creating garden space in a short period of time.
We did this in May 2010, and planted into it 2 weeks later, with a sprinkle of organic fertilizer and an extra handful of compost with each seedling. I had a really great garden the very first year. I think the buried straw layer was key - it made for good drainage and aeration, yet held onto enough moisture to make a good environment for roots and beneficial microbes. And no weeds to speak of.
Last year(2011)I topdressed with a thin layer of grass clippings, 1" of compost and one of topsoil. Again - a very good growing year. This winter I planted a cover crop of annual rye on one part, mulched with 6" of straw on another part, and covered a third part with a low tunnel for lettuce, spinach, beets, kale, and cilantro. It was mild winter, so I have been harvesting lettuce the entire winter long in my zone 6 garden.