From Compacted Clay to Thriving Garden: Build Soil Quickly with Lasagna Gardening
This ancient method transforms even the worst dirt into thriving healthy soil.
No, it has nothing to do the Italian pasta dish.
“Lasagna gardening” is a method of building rich soil.
It was one of the very first ways I learned to grow food when I started organic gardening 7 years ago.
My mentor and dear friend was a German horticulturalist named Marielu. She implemented what German’s call Hugelkultur raised beds all over her self-sufficient homestead, and let me tell you: the place was THRIVING.
Starting with compacted hard clay
But our new garden was rock-hard clay, basically concrete.
I asked Marielu how we would ever have a garden like hers if the soil was so terribly compacted.
She grinned: “I started with the same exact clay that you have”.
The Hochbeet or Hugelkultur (German for “raised/mound bed”) method is a practical way to create a self-fertilizing, composting raised bed. It has been used for centuries all over Europe.
The process is simple: pile different organic matter on top of each other to create a raised garden bed with zero tillage or digging.
This is also sometimes called a “lasagna” garden or “sheet composting” because of the layering.
Not to be confused with certified organic farming, organic matter is basically just dead plant and animal material like branches, twigs, straw, leaves, woodchips, manure, and compost. Think of what would be decaying on the forest floor.
Microorganisms decompose these materials into soil organic matter (SOM), which is the foundation of soil health all over the world.
First, gather your materials
Growers can use whatever organic materials they have readily available in their area (often for free).
You’d find us on the side of the road piling leaves into bags (from yards and parks that we made sure were not sprayed with herbicides).
We gathered 1–3" diameter branches and twigs from a nearby forest.
We contacted a local farmer for rotten hay (it is getting buried, so need to worry about weed seeds).
The only thing we had to buy was finished (not hot) compost and a bit of topsoil.
When to make lasagna beds
The best time to build and establish your Hochbeet is in the fall because yard clippings and rough materials are readily available.
This also gives the organic matter some time to begin breaking down before spring. But don’t worry, you can start building soil any time of year!
In wet climates, you should cover the beds with a tarp and weigh it down with bricks for the winter to prevent it from getting waterlogged.
In a dryer climate, you need to ensure that the bed stays somewhat moist.
If you need to plant immediately and don’t have time to over-winter the bed, make sure the top 5–10 inches are a good quality top soil.
If you do not have raised garden beds, you can use this method in a mound/hill or even in a large container garden.
Once you have your beds built and your materials gathered, assembling the Hochbeet is fairly easy.
Layers of the lasagna garden
Layer 1: Thick weed-smothering materials
Newspaper or cardboard are highly recommended for the bottom layer if you have a lot of grass or weeds where you are establishing a new bed. These materials will suffocate the grass and weeds so they don’t show up in your garden later.
In our case, it was mostly just clay, so we attached our hardware cloth (fairly expensive heavy duty wire mesh to prevent mole issues) and went straight to layering larger sticks and branches.
Layer 2: Woody materials, sticks, and branches
Think about the woodiest or hardiest materials going at the bottom because they take the longest to decompose.
I wouldn’t recommend whole logs, but 1–5" diameter sticks offer an awesome food source for the beneficial fungi that will start growing in your new garden beds (fungi are super important for healthy soil).
Layer 3: Rough garden waste, smaller branches and sticks
Then, you will slowly work your way up to the lighter materials that decompose more quickly. I added some smaller twigs on top of the branches as well as prunings from some perennial shrubs.
Layer 4: Kitchen scraps, aged manure, grass clippings, coffee grounds
Next up you can get more diversified with more nitrogen-rich materials. We added rabbit manure, chicken manure, grass clippings (make sure the grass has not ever been sprayed with herbicides), and coffee grounds from a local roaster. Go hunting around town for biodegradable waste materials and you will be suprised what you find! Plus, it makes for some interesting conversations.
*Hose down the layers as you go to keep them moist, but never soggy. The beneficial microbes that are going to break down all this material need moisture, but they also need oxygen, so you want to keep the environment aerobic (oxygenated).
Layer 5: Leaves, pine needles, straw, fine bark
Deciduous broadleaves are by far the best option here. Our leaves had been partially decayed in a pile that sat through the fall. They were mostly maple leaves and some pine needles. Many of the “warnings” regarding certain types of tree leaves being poisonous to garden plants are actually myths. As long as you have diversity, your plants will thrive!
Layer 6: Compost and/or fine top soil
The layers should be alternated between browns (aka carbon rich materials) and (greens aka nitrogen rich materials). I threw some soil and compost in between layers too.
At the very top is about 4–5" thick of rich well-made compost and then a few inches thick of topsoil. This makes for a beautiful bed ready for planting!
There aren’t any hard fast rules; lasagna gardening is all about using the organic matter available in your local area. The most important thing is to end with a layer of finished compost and a thick layer of topsoil, as detailed in the photos below.
Why it works
The layering method creates a rich environment for plant growth because it builds soil from the top-down.
It’s almost like piling new living soil on top of your existing dead dirt.
The microbes go to work enriching that area without you needing to mechanically disrupt it (ie. no tilling required). This makes lasagna beds especially useful in areas of hard compacted clays or otherwise difficult soils.
Lasagna gardening is a biological rather than mechanical approach to building healthy garden soil.
Of course, the concept is nothing new. Mother Nature has been doing it for thousands of years!
The layering of dead plant and animal materials mimics a natural forest or grassland ecosystem. As leaves, branches, and animals die up above, they fall to the Earth and decay (thanks to the power of microbiology).
Lasagna-style gardening pulls from centuries-old methods of growing food such as the “Hugelkultur” model from Germany that Marielu used, as well as the layering or piling of organic matter used by native cultures around the world to cultivate rich agricultural soils.
The method is even used on modern-day, high-production farms!
This simple, affordable, and quick method of building soil can turn a degraded garden into a thriving oasis.
Your plants and stomach will thank you!