A no-dig bed is composed of layers, and as the name suggests, there is no digging involved. Below is an example of the layers in a no-dig bed. This nifty display was made by a talented friend for use as an educational tool at one of our local permaculture stalls.
The first (i.e. bottom) layer is placed directly on the mown grass and is generally something like heavy cardboard, thick layers of newspaper or old wool carpet. It's important that this layer is made of natural materials so that it will eventually decompose. This layer acts to smother the grass below and kill it by the time the material in the layer has decomposed. The pieces in this layer are overlaid so that the grass is completely covered and it is then wetted to compact it and remove any gaps.
Here's a picture of the bed being made at our place. The first step was to outline the edge of the bed with some second-hand bricks we had collected. The bed along the fence line in the right of the picture was made earlier using the same no-dig method.
Once the outline was complete, the cardboard was laid down. We sourced the cardboard from my workplace, and from the local deli. They were happy to give it away.
Once we had the cardboard in place we dug a snug channel to lay the bricks in so that the top of the brick was level with the ground. Newspaper layers placed around the edge of the bed (tucked under the cardboard) were positioned to extend into the channel and up the other side towards the lawn. The bricks were placed on top of the paper in the channel. This was done to create a barrier and further discourage grass from the lawn growing into the bed. We then added another row of bricks on top of the first row to help keep the rest of the layers in the bed.
Then it was time to add the lawn clippings, leaves, compost, dirt, and whatever else we had on hand. We weren't in any rush to plant into the bed so we didn't really worry too much about following strict guidelines of what should go in the layers. We wanted to recycle the nutrients from our garden and just use what we had. If you are wanting to plant into the bed relatively quickly then it's better to follow the recommended layer recipe.
Over time and with the addition of our home-made compost, the soil in this bed has become rich and full of worms, making it very productive. Asparagus, rhubarb, various herbs, lettuces, silverbeet, cape gooseberries, raspberries and boysenberries now surround the original fruit trees in this bed. In fact it's hardly recognisable from the early photos. The brick channel we dug has done a great job of stopping the lawn growing into the bed. We even made a further smaller no-dig bed just in front which contains our babaco and strawberries:
Making a no-dig garden bed is easy and involves none of the backbreaking effort that would otherwise be required to dig up the lawn. We wouldn't make our garden beds any other way!