Build a lasagne bed in five steps

If you’re taking advantage of the slower winter months to build new garden beds, the “lasagne” method is a great way to ensure they’re as productive as possible when it’s time to plant in late spring or early summer.

Lasagne gardens are raised beds made up of a range of compostable material that, layered on top of one another, help to suppress weeds, retain moisture, and provide organic matter for the formation of rich soil teeming with beneficial microorganisms.

While there are variations on the ingredients used, lasagne beds most often use a combination of older “brown” materials such as cardboard, logs and branches, leaves, straw and hay, and newer “green” materials such as compost, kitchen scraps, manure and fresh grass clippings. By adding alternate layers of brown and green materials, you can ensure the soil ends up light, fluffy and well draining, yet is full of moisture and nutrients.

STEP 1: Identify and measure off an area for the bed location in a sunny spot. This can either be directly on top of grass or an old garden bed. Construct the bed framing with your chosen timber according to your preferred dimensions. Macrocarpa or redwood sleepers are a great, robust option if you’re wanting to avoid treated wood. I prefer 200x50mm sleepers stacked three widths (60cm) high. To make it convenient and efficient to tend to your garden, you should locate it within view and easy walking distance of your kitchen.

STEP 2: Lay down a layer of cardboard at the bottom of the bed, ensuring the pieces are overlapping and completely covering the grass. Drench the cardboard with water. If you’re wary about any adhesives from the cardboard absorbing into your soil, an alternative is to lay down lengths of logs according to the hugelkultur method. The logs not only suppress weeds, but they act as a kind of sponge at the bottom of the bed, retaining moisture in dry weather and slowly depositing nutrients as they decompose.

STEP 3: Add a 10cm layer of brown material such as dead leaves, sticks, hay or another kind of mulch, followed by a 10cm layer of “green material” such as manure or kitchen scraps. Repeat the process until you reach your desired height.

STEP 4: Finish the bed with a layer of good topsoil, topped with a layer of mulch to protect it from the elements.

STEP 5: Wait until late spring or early summer to plant, after the materials have decomposed and released their nutrients into the soil. If you’re wanting to plant sooner, add a 20cm layer of compost on top of the bed and plant straight into it.