In many building instructions for raised beds, you can find the instruction that the bed frame should be lined with a robust and waterproof film to protect it from moisture. Otherwise the material of the frame will suffer, and in particular the lifespan of a wooden bed can be reduced by up to five years. However, many commercially available films contain harmful substances.

Pond liner is ideal for raised beds

Can a raised bed be built without foil?

Of course, you can also do without the foil when building your raised bed. In this case, however, you will not enjoy gardening for long, especially with a wooden raised bed, because the consistently high humidity in combination with the considerable heat development not only promotes rotting of the bed contents. The wood of the frame also decomposes very quickly, and fungi can also colonize it. If you want to avoid using foil, you should use a water-resistant frame that makes cladding superfluous: raised beds made of Corten steel, high-quality aluminum or stone can do without the protection.

Advantages and disadvantages of different foils for raised beds

Otherwise, it is worth taking a close look at the different materials, because not all films contain harmful plasticizers.

pond liner

Pond liner is actually produced especially for the construction of garden ponds and combines a whole range of desirable properties that are also very useful for raised beds. So are pond liners

  • pretty tough
  • tear resistant
  • Can be flexibly cut and laid
  • waterproof
  • and often UV-resistant.

The last property in particular is a very useful one, as exposure to sunlight causes many films to become porous and disintegrate over time - not so UV resistant films that you basically buy once for life. Pond liners are made of different materials, but not all of them are suitable for a raised bed.

PVC film

PVC film is definitely not recommended in raised beds: it contains plasticizers as well as many other pollutants that are released into the earth over time and from there migrate into the vegetables.

EPDM foil

In contrast, biologically harmless EPDM foils, which consist of natural rubber, are generally free of harmful substances. However, these are very expensive, but also last extremely long.

Dimpled or drainage film

Bubble wrap is a drainage material that helps prevent waterlogging in raised beds. Actually a fine thing, but pay attention to the material used. Many inexpensive bubble wraps consist only of PVC or other components contaminated with pollutants.

tips

Instead of using foil, the raised bed frame can also be covered from the inside with thin, untreated hardwood slats (e.g. larch). These also keep moisture out and are free of any pollutants - but they slowly rot away and have to be replaced after a few years. In addition, fungi can grow on permanently damp wood.

Category:

Vegetable garden