Lasagna bed gardening is a layering technique that lets you create a garden without digging or tilling… or improve an existing bed in one day.
A lasagna garden normally sits above the ground but can also be used to improve the soil in in-ground beds. Instead of filling with only fresh soil, you will stack compostable materials like newspaper, cardboard, sticks, leaves, and grass clippings in with compost and soil. Over time the compostable materials will decompose and turn it into a rich, nutrient-dense soil of its own.
Lasagna beds are a way to grow organically and use less water, since many of the decomposing materials help retain moisture.
The ideal lasagna garden bed uses a mix of 4 parts high-carbon to 1 part high-nitrogen ingredients.
- High-carbon materials. Think of these as your brown layers. You can include things like small pieces of tree trimmings, sticks, peat moss, dried leaves, straw, mulch, and sawdust. If you use sawdust, consider that many lumber products are treated and should not be used.
- High-nitrogen materials. These are your green layers. Include materials such as grass clippings, vegetable scraps (or produce that’s past its prime), coffee grounds, and even manure from plant-eating animals.
- A base layer: for a new bed, cover the area in newspaper or cardboard; for an existing bed, start with a layer of sticks and tree trimmings.
- Note: If you use sticks and leaves, smaller pieces are better. I purchased a small leaf shredder for the leaves and small sticks. Smaller decomposes quicker and allows water to pass through easier.
Stack your lasagna layers as follows:
- Base layer (See description above. You will only need one Base layer.)
- A high-carbon (brown) layer, keeping your 4:1 ratio in mind.
- A high-nitrogen (green) layer about ¼ as thick as the carbon one.
- A thin layer of good compost alternated between layers will assist decomposition.
- Repeat this process until you reach your desired height (18-24″ inches tall is ideal).
Timing:
If you’re creating your lasagna garden in the fall, you can wait for your lasagna bed to turn into a rich, nutrient-dense soil. Or, if you start in the winter or early spring, you can plant seed and/or started plants directly in your bed after the danger of frost has passed. A top layer of soil will help your seeds get started but be sure that the manure/compost is fully composted before planting.
During the growing season, continue to follow the 4:1 ratio while adding compostable materials to the top to keep a steady supply of new nutrients coming into your plot. In future growing seasons, add alternating layers to the top as needed.
by Rob Franks, ECMG