At the Horticultural Research Station (Lehr- und Versuchsanstalt für Gartenbau) in Bad Zwischenahn, 15 "alternative" pots were tested. These pots were made from recycled materials or bioplastics (some of which are biodegradable) from different manufacturers. Calluna vulgaris 'Helena' was cultivated in these pots in the field for a period of 25 weeks in accordance with standard practice. No significant differences were observed in surface fresh weight. However, only pot no. 5 (Jiffy Sphagnum pot R2) showed significantly lower root growth in comparison to the other variants. It was evident that pots 4 (Evolutio GmbH), 5 and 6 (Jiffy), as well as 13 and 14 (Golden Compound), showed the most pronounced visual changes (i.e. signs of degradation) during the trial period. This phenomenon was accompanied by a substantial loss of structural stability.
