With incredibly well established crabgrass, killing it organically in order to create garden beds, tree planting sites, etc. seemed like quite a challenge. As time is on my side, I elected to lasagna garden!
The concept is simple.
- Existing plants (turf) are mowed down as low as possible.
- A biodegradable barrier is put down to smother out the existing turf. I used cardboard as businesses are happy to give it away but brown paper bags and even multiple layers of newspaper are adequate.
- Compostable layers are laid down on top of the biodegradable barrier: Anything compostable: mixed nitrogen/carbon (green/brown) material, manure, mulch, etc.
Working simultaneously with the composting materials from step 3, the layer in step two smothers out the established turf before composting both that now dead plant material and the barrier itself. Between the organic matter used in this procedure and what is provided in the roots of the existing, smothered plants, the worm and microbe activity will be exceptionally high yielding quality soil for planting in the following season.
Don’t forget to remove all tape, glue and staples from the cardboard. Also avoid glossy cardboard as it is coated in plastic.
Here are some pictures of my process.
Measuring 6 feet between beds (4 foot bed plus 2 foot aisle). These dimensions are simply my preference. Being 6’4″, there is nowhere I can’t easily reach in a 4 foot bed. Plan your garden beds to your preference!
Fill with compostable layers (composting manure in my case) then mulch with whatever you have available to inhibit weed growth. I also planted a cover crop of red clover as an experiment. It seems to be germinating best where the compost is old or where some soil was mixed into the manure compost such as where I excavated to install root barriers in the middle of some garden beds.
In retrospect, I can use old pictures to show the process from start to finish!
Lasagna bed being built in November of last year:
Asparagus planted into that bed in May. All but the very top layer of manure had composted:
3 weeks later in June:
I also use this method for establishing flower beds or tree planting sites. Here is a little filbert (hazelnut) seemingly content in his lasagna bed: