In many building instructions for raised beds you can find the instructions that you should line the bed frame with a robust and waterproof film to protect it from moisture. Otherwise, the material of the frame suffers, and the lifespan of a wooden bed in particular can be shortened by up to five years. However, many commercially available films contain harmful substances that are harmful to he alth.
Which film is suitable for raised beds without harmful substances?
EPDM films made from natural rubber are a pollutant-free and robust alternative to PVC films for raised beds. When using studded or drainage films, also pay attention to low-pollutant materials. Another option is to cover the bed frame with untreated hardwood slats.
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 be able to enjoy gardening for long, especially with a wooden raised bed, because the constantly high humidity combined with the considerable heat development not only encourages the contents of the bed to rot. The wood of the frame also decays very quickly and fungi can also colonize. If you want to avoid using foil, you should use a water-resistant frame that eliminates the need for cladding: raised beds made of Corten steel, high-quality aluminum or stone can do without the protection.
Advantages and disadvantages of different films for raised beds
Otherwise it is worth taking a closer look at the different materials, because not all films contain harmful plasticizers.
Pond Liner
Pond liner is actually produced specifically for the construction of garden ponds and combines a whole range of desirable properties that are also very useful for raised beds. This is what pond liners are like
- very robust
- tearproof
- can be flexibly cut and laid
- waterproof
- and often UV-resistant.
The last property in particular is a very useful one, because exposure to sunlight causes many films to become porous and fall apart 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 both plasticizers and many other pollutants that are released into the soil over time and from there migrate into the vegetables.
EPDM film
Biologically harmless EPDM films (€536.00 on Amazon), which are made of natural rubber, are generally free of harmful substances. However, these are very expensive, but they also last extremely long.
Pimple or drainage film
Pimpled film is a drainage material that helps prevent waterlogging in raised beds. Actually a nice thing, but be sure to pay attention to the material used. Many cheap bubble wraps consist solely of PVC or other components contaminated with harmful substances.
Tip
Instead of a film, 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 harmful substances - but they slowly rot and have to be replaced after a few years. In addition, fungi can settle on permanently damp wood.
