This is one technique that I recently learned about and just absolutely fell in love with! Mostly because (in my opinion) the biggest deterrent to starting a garden is the idea of ripping up the sod, and tilling. The process is so labor intensive and then you have to figure out a place to put all of that plant matter you have removed from the ground. If you feel the same, then you're probably going to just love this idea. Next time you plan on starting a garden, don't rip up grass, and don't worry about raking up and removing the plant matter from the plot you've cleared, simply layer over it! Yes, that's right, plan on just going right over it!
I know it seems pretty crazy, everything we learn about planting a garden seems to tell us to rip out those weeds and get them as far away from the plants you want as possible. However, one of the biggest points of permaculture farming/gardening is that you want to do everything you can to encourage proper soil health. Healthy soil is living soil, it is full of decaying plant matter that encourages worms to be present, and it should smell like the dirt on a forest floor. Personally, I love the smell of dirt on a mountain trail, just something about it makes you feel so grounded (ha! I crack myself up).
So how do you do it? It's not completely labor free, but honestly compared to the alternative it's like the difference between running through a waist deep field of grass, or through waist deep water. Here's a basic how-to:
1. Look at the area you want to plant, and decide what kind of soil you want out of it (basically if you need acidic soil, add some acidic plant matter, like pine needles etc). Determine what you need to add to the base layer, and mark out the area you will be turning into your garden.
2. Mow/Cut/Knock over the plants. You want everything laying flat, but you also want to remove the large pieces of plant matter (branches, thick stems). Basically if you can't step on it and have it lay flat for a bit after then get rid of it.
3. Put your initial layer of compost/mulch down, and soak it with water.
4. If you have any trees or shrubs to plant, do so now, but be careful to not pile up compost/plant matter too closely to them as you prepare the rest of the layers.
5. Place your layer that will act as a weed barrier. You can use anything biodegradable here, but the most common choices are newspaper/cardboard. You will need about 3-6 layers of newspaper, and you need it to be a nice even cover, with the edges overlapping quite a bit, the point here is to prevent weeds from popping through. After you have that placed, do yourself a favor and wet it down a little to keep it from flying away as you complete the next couple of phases.
6. Layer mulch/compost on top of the weed barrier. Basically this layer mimics the way a forest floor works, you have plant matter and dirt layered to help break down everything below it by encouraging beneficial insects to be present. So aside from compost you can layer in wood chips, dead leaves, straw. Basically put the compost down first and then the plant matter on top of it, your goal is at least a 2 inch top layer.
You can plant seedlings in the mulch/compost layer, or more well established plants can get planted right below the weed barrier by poking a hole right through it for the plant. This is also something you can pretty much do for free if you plan it just right. Personally, this fall as I rake leaves I am going to get some cardboard/newspaper from the bins at the dump and harvest some local dirt to get my garden plot mulching before the snow falls. Doing it this way means that come spring my garden will be all ready for planting and the soil should be enriched by the plant matter that had all fall to decay and turn into compost.