How much formaldehyde do cardboard boxes contain

Possible pollutants Can cardboard be placed on the bed or on the compost?

It is not so easy to find out who is right. Theoretically, cardboard and paper are made of cellulose and are made from trees, making them a natural substance - and low in pollutants. But that is exactly a fallacy, says Ulrich Zang. The geoecologist is a specialist in compostability tests at ISEGA - a testing and certification institute.

Cardboard is usually a high-tech product, which can be composed very differently.

Ulrich Zang, expert for compostability tests, ISEGA

Cardboard and paper always contain additives. Usually it is between five and ten percent. In addition to inorganic fillers or auxiliaries such as calcium carbonate or talc, there are many other additives such as wet strength, glue or binding agents. For example, they ensure that the paper does not dissolve too quickly when it comes into contact with water. Biocides (against mold or pests), dyes and other technical aids may also be present in lower concentrations. In addition, products such as paper carrier bags, cardboard folding boxes or moving boxes usually contain printing inks and adhesives.

There are hardly any limit values ​​for pollutants in cardboard

But these substances are not necessarily toxic. It is the dose that makes the poison. "It's nonsense to believe that pure cellulose is free of harmful substances. In principle, harmful substances are everywhere. Also in so-called natural products," says Zang. So it's always about limit values ​​and what might or might not harm. In addition, microplastics are becoming more and more important. The main problem here is the accumulation in the soil.

Unfortunately, "Blue Angel" is not a helpful seal for this question

In order to decide whether the cardboard is allowed in the garden or not, there should be limit values ​​that can be used as a guide. But there is no such list for the use of cardboard in the garden. The "Blue Angel" seal, which can be found on many papers, is unfortunately of no help. For example, the seal on some products guarantees that this product is made from waste paper, contains no more than five percent additives and has not been treated with chlorine or optical brighteners. On other products it stands for an environmentally friendly production method. The eco-label says nothing about compostability, because neither paper nor cardboard is made for it.

Cardboard and paper are designed for recycling - and that works well. The added substances even help. "They make sure that the recycling cycle works," says Zang. And Almut Reichart from the Federal Environment Agency adds: "Cardboard is a valuable raw material that should be recycled and not used in the garden for purposes other than intended."

The use of cardboard from retail stores to cover flower beds is not the intended use of such packaging.

Almut Reichart, Federal Environment Agency

Can the cardboard go into the garden or not?

"For example, you could apply the standards for compostability," says Zang. Among other things, these regulate the amount of heavy metals that may enter the material cycle through the product. The question of that Decay, which in common parlance with Compostability is equated is only a relatively insignificant aspect here.

Paper products that are certified as compostable undergo an extensive test. Not only must the amount of harmful substances be verifiably reduced to a minimum, but generally no ecotoxic effects must be detectable. In addition, the substances must biodegradable be actually "processed" by microorganisms - and not remain in the ecosystem in the form of tiny microparticles. But of course there are limit values ​​here too for technical reasons - and that is a point of arguing.

Now most gardeners will not create large compost heaps with cardboard and thus accumulate potential pollutants. Most of them will cover a bed here and there or throw a toilet roll on the compost. Perhaps they also stick to the tip sometimes given to only use unprinted cardboard from the food sector - such as banana boxes. Perhaps the cardboard will then fall apart on the bed and be eaten by the earthworms. That looks good to gardeners' eyes. Still, nobody knows what gets into the ground with it.

No layman can tell what's in the cardboard that he is distributing in the garden.

Ulrich Zang, expert for compostability tests, ISEGA

But one should keep an eye on the proportionality: If there is a football field with artificial turf next to the garden, a multiple of microplastics will probably end up in the earth. The same applies to other pollutants. Nevertheless, if you want to be on the safe side, put the cardboard in the blue bin.