Fungi growth prevention on pulp-based plant pots: deskstudy

Modiform develops and produces growing, transport, and packaging systems for the horticultural sector and beyond, delivering more than 10,000 unique articles across the world. They source materials from society and upcycle these into high-quality, smart, and sustainable products. Modiform’s new product series EcoExpert is made from 100% recycled paper and cardboard. The pots and trays can be disposed of through the standard consumer or retailer cardboard recycling system, but if they find their way into the natural environment they will compost within a year. Their current products suffice in retail applications (average service time of 4 weeks) but occasionally fungal growth is observed. Modiform wants to prevent fungal growth and prolong the service time of their EcoExpert pulp based plant pots with the ultimate goal that they can be used as growing pots. Solutions should not hinder de biodegradability of the pulp based pots, should be safe and are preferably based on natural substances. Moreover, they would also like to learn more on fungal growth and especially if these fungi are hazardous to public health. Wageningen Food & Biobased research has extensive expertise with respect to the development of products based on renewable resources including (paper) pulp. This knowledge also includes the modification of these products and as an example WFBR has studied environmental friendly solutions to prevent mould growth in wood and extending the service time of natural fibre based agricultural substrates. Additionally, WFBR has extensive knowledge on microbial safety of products and the effect of environmental conditions on fungal growth. Fungal growth depends on the environmental conditions (humidity and temperature), the accessibility and nature of the growing substrate and the presence of fungal spores. As the type of fungal spores present will be uncontrolled, predicting the type of fungi that will contaminate the plant pots is impossible. Still, some insight in typical fungi that grow on cellulose can be provided. However, the focus of this deskstudy is on preventing fungal growth. This deskstudy provides insights from experts at Wageningen Food & Biobased Research and from academic literature but considers the commercially available biobased and environmentally safe solutions, such as antifungal additives (i.e. fungicides), antifungal coatings and combinations thereof. The results of this study enabled a recommendation to implement a coating solution containing an essential oil or a mixture of essential oils; where a hydrophobic material would be used as a matrix material (e.g. vegetable oil wax) due to its ability to control the release of active anti-fungal substance and water barrier property.