Raised bed: which film / fleece to choose for the inner lining?

With a raised bed, the joys of gardening can be experienced even in the smallest of spaces or in old age. This unique bed shape requires a special structure with several layers of soil, compost and Green waste stored in a bucket higher than the actual soil is available as a vegetable garden or flower bed stand. The inner lining is important for the bed. This protects the plant vessels, which are often made of wood, from the moisture from the substrate.

Why foil?

The inner lining is an essential part of the raised bed, as it protects the sensitive outer material from the constant moisture from the soil and compost. Raised beds made of wood, in particular, have to be lined with a film on the inside, otherwise they will start to rot and have to be replaced after a few years. On average, a wooden bucket lasts around five to ten years if it is not clad accordingly, which does not do justice to the considerable effort involved in setting up it. It's not just the wood that rots here:

• high moisture in the earth hits the wood
• it creates heat
• Moisture draws into the wood
• rotting is initiated due to the heat and moisture
• Rotting affects wood and its contents
• The contents of the bed are rotten
• Wood rots inside and crumbles
• Fungal colonization is possible, which has a negative effect on plants

It is therefore important that you integrate the foils into the project in order to protect the bed over a long period of time and, above all, to be able to enjoy it. They ensure the longevity of the bed if you do not use materials that are waterproof and cannot rot.

Which inner linings for the raised bed?

Since a large part of all textiles and fabrics that humans can produce from nature also rot or to get slightly damp, you have to put on foils or fleeces made of rubber or plastics will. This includes:

• Pond liner made from different materials
• Bubble wrap
• PET fleece

You should definitely refrain from using classic PVC films, as they contain the largest amount of plasticizers that have a harmful effect on plants, animals and humans. Due to the moisture, these are quickly absorbed into the substrate and can literally "poison" crops in particular. If, for example, you were to line your raised bed with PVC sheeting and plant potatoes, the plasticizers could pull into them and then damage your health. Therefore, when choosing a suitable raised bed sheet, you should ensure that the sheets used do not contain any or only harmless amounts of plasticizers.

Pond liner - the classic

The pond liner has been used for decades to create your own small bodies of water in the garden without them seeping into the ground. For this reason, pond liner is suitable for lining the raised bed. Even small raised beds can be lined with this fabric without requiring a lot of work or knowledge. The biggest advantage of the pond liner is its high flexibility, because it was designed to hold water of different volumes without tearing. You can use this film to provide beds of different sizes at low cost, but you have to pay attention to the different materials and compare them:

• PVC
• PE
• Liquid pond liner
• EPDM

Note: Never use normal plastic sheeting, such as tarpaulins that you can use to cover a vehicle. These not only have a negative effect on the growth of the plants, but also tear easily, shrink and often become leaky.

PVC

A large part of the pond liners offered is made of PVC, polyvinyl chloride. PVC is one of the most frequently used types of plastic and is mainly used for pipes, as the polymer can withstand different heat effects and is quite easy to manufacture. The advantages of PVC pond liners are:

• smooth
• elastic
• is easy to lay
• can be easily adjusted to corners
• extremely hard-wearing
• resilient under great weight
• can be easily repaired
• Available in numerous colors, but rather unimportant for raised beds

Theoretically, such a film would be perfect for the raised bed. However, PVC films are extremely harmful to the environment and have by far the largest amount of plasticizers compared to other plastic films. That doesn't make them ideal for use in a raised bed. Due to these plasticizers, they are also more prone to damage, since instead of water there are several layers of heavy, moist soil, compost and plant residues in the bucket. The PVC film often dissolves and leaves small holes through which the earth in turn touches the wood. You should absolutely refrain from using conventional PVC film.

PE

Films made of PE and polyethylene are an alternative to classic PVC. Polyethylene is also a thermoplastic and can be used quite well as an interior lining for small raised beds, as the fabric is quite stiff. He needs a little more time to undress, but the environmentally friendly value of the film should be mentioned. The plastic is biodegradable and leaves no residue. Although PE has a shorter lifespan than PVC, it does not emit any toxic fumes into the earth and can therefore be used without hesitation. Furthermore, the PE films are UV-resistant, but this is not important for a raised bed.

EPDM

The most expensive, but at the same time most durable, variant is made of ethylene-propylene-diene rubber. In contrast to PVC, EPDM foils are in many ways more effective and are perfect as an interior lining in raised beds:

• certified organic
• no vapors, little plasticizer
• tearproof
• stretchable up to 300 percent
• high elasticity
• tolerates temperatures down to -40 ° C
• extremely durable
• ozone-resistant substance

Due to its effectiveness, this film can be used for several decades without having to be changed once, which makes it very advantageous for raised beds. Despite the small amount of plasticizers, they are not harmful for use in beds. When lining, make sure to do this very carefully, as EPDM foils make it more difficult to line raised beds than other pond liners. Due to the relatively small dimensions of raised beds, however, this is still easier than with large ponds or long streams.

Liquid pond liner

The use of a liquid pond liner instead of a normal variant sounds quite modern. As the name suggests, this is a liquid form of the pond liners that can otherwise be laid, and for this reason it is not laid over sheets. The liquid film is generously applied directly to the wood of the raised bed with a brush, roller or spray can and then left to dry. Then the different layers of soil can be poured in. The biggest advantage of them is their food safety, which makes them safe for use in a raised bed. Well-known manufacturers are Tripond and Impermax.

Bubble wrap

Any kind of bubble wrap is perfect as an inner lining for a raised bed. This film is easy to lay, does not contain any plasticizers and ensures effective drainage due to the knobs. Here the water can easily flow down without collecting between the foil and the wood. But these are not all the advantages of the bubble wrap:

• resistant to chemical agents and wear
• root-proof
• impact resistant
• tearproof
• pressure resistant
• withstands temperatures in the minus range without any problems
• drinking water neutral

The numerous knobs on the film are particularly effective on this film. It is attached to the wood with the knobs and the raised bed receives effective air circulation and drainage. When using bubble wrap, you should also pay attention to whether it was made on simple PVC. Although dimpled sheets for the garden area in particular are not provided with plasticizers, it can always be the case that a manufacturer does only uses PVC and no more environmentally friendly materials, which in turn has an impact on the quality of life of your plants can.

PET fleece

The PET fleece is a fleece that was specially developed for use in the garden and works extremely well against moisture in raised beds. The fleece consists of polyethylene terephthalate fibers (PET), which belong to the polyester family. Polyester is a popular fabric for modern, breathable clothing that can even be water-repellent. These properties are also transferred to the PET fleece. The fleece has the following properties:

• can be easily cut to size
• works against pests
• very easy
• lets water through, but not the earth
• frost resistant
• weatherproof

The fleece cannot rot and is therefore perfect for use in raised beds. This gives you an easy-to-install alternative to foil, which is also particularly lightweight. Another advantage is resistance to roots.

Materials for beds without foils

If you don't want to use foils, you can also use materials other than wood for your raised bed. Not only are there numerous substances in nature that are waterproof, but humans have also developed suitable materials, which should be mentioned here. These include:

• aluminum
• stainless steel
• Edelrost, corroded steel sheets, also known as corten steel
• stone
• Plastics, but these can also contain plasticizers

These materials do not require foil as they are not themselves made from natural substances that could rot. A Mediterranean-stylized raised bed made of stones is just as enchanting as a modern accent made of stainless steel. They show no form of material fatigue and can easily be refilled every year if the soil layers of the bed have to be renewed. Such alternatives are particularly suitable for you if you do not want to get additional sheeting and use it to line the beds. In addition, the following types of wood should be mentioned that are particularly resistant to moisture:

• teak
• larch
• Douglas fir
• Azobe
• Bankirai
• Black locust

These can also be used without foils, and despite the fact that they may rot, they clearly withstand longer than other types of wood.