Raised beds for every garden

Yes, that is possible, but not recommended. Plain soil compacts quickly, settles and provides fewer nutrients than a traditional layered structure. If you do choose to use only soil, you should opt for high-quality raised-bed compost rather than ordinary garden soil. Without a layered structure, the greatest advantage of a raised bed is lost: the natural heat generated by decomposition.

If the layers are laid up correctly, drainage is not necessary, as the bottom layer of coarse branches and twigs automatically acts as a drainage layer. On sealed surfaces such as concrete or a balcony, an additional drainage layer of expanded clay is advisable to prevent water from pooling and the roots from dying. Expanded clay is better than gravel, as gravel retains cold.

You can plant a raised bed from March onwards with hardy crops such as lettuce, spinach or radishes; with a fleece cover, you can even start a little earlier. Heat-loving plants such as tomatoes or courgettes should only be planted after the ‘Ice Saints’ in mid-May. Lamb’s lettuce, a typical autumn and winter crop, can be sown from August onwards and can even withstand light frost in the bed. This means the raised bed can be used almost all year round.

Tomatoes, courgettes, peppers, lettuce, radishes, Swiss chard and herbs thrive particularly well. In the first year, heavy feeders in particular benefit from the nutrient-rich layers; after that, it is advisable to switch to medium and light feeders. Plants that require a lot of space, such as pumpkins or maize, are less suitable as they take up too much space. Flowers such as marigolds or nasturtiums can also be grown alongside them and help keep pests at bay.

Fennel should not be planted in the same raised bed as other vegetable plants, onions and beans, or tomatoes and cucumbers, as they require different levels of moisture. Fennel inhibits the growth of almost all types of vegetables and should be planted separately. Never grow brassicas in the same spot for several years, as this encourages disease. Planting too densely also encourages powdery mildew.

In winter, you should cover the raised bed and not leave it empty. Remove any leftover produce and cover the surface with mulch, leaves or green manure. Never leave the bed empty and uncovered, as this will cause nutrients to be washed away. Winter vegetables such as lamb’s lettuce or kale can be left in the bed. Water occasionally on frost-free days; soil life needs some moisture even in winter.

Raised beds can be protected from voles by placing a fine-mesh wire mesh at the base, and from snails by fitting a snail barrier around the edge of the bed. The wire mesh should have a maximum mesh size of 13 mm and should be fitted during construction; retrofitting it is virtually impossible. Another way to deter snails is to water in the morning rather than in the evening, as dry surfaces keep snails away. Do not apply a layer of mulch directly at the edge.