Raised beds are great for growing vegetables, herbs, edible flowers and berries like strawberries, blueberries and currants. They’re especially useful for gardeners with limited space or poor, compacted or poorly drained soil. Raised beds are also easier and more enjoyable to maintain, since you don’t need to bend over or crouch to reach the soil and plants.
This approach isn’t really new. Many gardeners grow their vegetables in 10 to 15 cm hilled beds, to improve their drainage. For a raised vegetable bed, you need a frame or sides to retain the soil, with the top 15 to 45 cm above the surrounding soil. Make your bed no more than 120 cm wide, so that you can reach into the centre of it without stepping on the soil.
Raised vegetable beds have a number of advantages (and a few drawbacks) as compared with traditional vegetable gardens.
- They maximize the use of space, since you don’t need paths between the rows of vegetables.
- They are a good solution for sloping or hard-to-work sites.
- They can be filled with fertile, humus-rich, porous soil, for better yields.
- Raised soil drains and warms up more quickly in spring, so that seeds germinate and seedlings root faster.
- They make it easier to reach the soil and plants, so they’re simpler to tend and harvest.
- They can be planted more densely, for higher yield per square metre. This also crowds out and cuts down on weeds.
- Well-drained soil can be worked much sooner after a heavy rain.
- If well-designed, they’re attractive.
- They tend to dry out faster during heat waves and hence need more watering.
- Initial costs are higher, to build the frame and add the soil.
- If densely planted, they may be more susceptible to disease problems.
- They aren’t well suited to growing sprawling vegetables (squash, cucumbers, etc.), although you can choose more compact varieties and grow them vertically.