The standard method
I usually fill new raised beds with a 1:1 mixture of compost (or rotted manure) and topsoil. If you don't have much compost, fill the bed with garden soil up to 10 cm below the rim and add a 5 cm layer of compost on top. Promote plant growth with liquid fertilizer and mulch the bed with a layer of compost every fall.
The composting method
Here, the bed itself serves as a compost heap. Although you can't plant anything until the second year, you'll get a very nutrient-rich substrate!
- Year 1: Fill the bed with easily decomposing materials, such as grass clippings and kitchen scraps. Twigs and wood chips are not recommended. The material should be well layered, thoroughly mixed at the beginning of each month, and covered with cardboard during the winter.
- Year 2: If you'd like to start growing something now, cut gaps in the cardboard box in May and plant zucchini plants. They require plenty of nutrients but little root space. Expect a massive harvest.
- Year 3 Now you can plant the bed as you wish.
The filling method
This method, based on the raised bed method (see below), makes good use of the topsoil beneath the lawn. However, you'll need a lawn on which to create the raised bed, as well as coarse organic matter to fill the hole (I use wood chips).
- Mark the location of the raised bed. Remove the turf and about 15 cm of soil.
- Place sod in the bottom of the hole, then set up the raised bed. Fill the hole and bed with organic matter up to 5–10 cm above the bottom edge of the boards – it will settle over time.
- Add the soil that was previously under the turf. Finally, fill the raised bed with home-made compost, if available.
The raised bed method
You don't need vast amounts of soil and compost for this, as it builds up different layers of organic matter. This method is particularly suitable for taller raised beds and relies on the materials gradually decomposing, ensuring long-lasting, sustainable access to nutrients for the crops. The bed also retains moisture for a long time during dry periods.
