Most gardeners accumulate plant pots, and while some can be re-used, disposing of the surplus can be a problem.
Recycling plastic pots
Plastic pots accumulate in landfill if discarded as rubbish and do not break down. Ideally, wash them to re-use yourself for raising more garden plants. A few garden centres operate recycling schemes and take back old pots, but recycling is only practicable where large numbers of uniform pots can be collected, as hand-sorting and cleaning make the process uneconomic.
The costs of transporting to a recycling centre, ‘pot miles’, must also be considered. Only plastics of the same grade and colour can be melted down for re-manufacture, and this also uses energy. If there is no recycling scheme in your area, consider donating surplus pots to local community groups, schools, hospice gardens or other charities.
Biodegradable plastic pots
These are rigid, like plastic, but are made from starch, sometimes modified by bacteria to make them insoluble in water. They can be re-used, and will last for two to four years. Insoluble bio-plastics can only be composted in a municipal heap where temperatures reach more than 60°c (140°F). Pots made from a mixture of soluble bio-plastic with some insoluble bio-plastic to prevent them from dissolving can be broken up and composted at home in 9–18 months.
Fibre pots
The RHS Advisory Service no longer recommends pots or propagating plugs made from peat, and there is also a question mark over the sustainability of coir. Although it is renewable and profitable for developing economies, transporting coir uses energy and depletes a natural resource from its country of origin. We recommend alternatives made from grass, bamboo, recycled paper and seaweed. These have their problems – they are less rigid, more expensive, and plants grown in them need more watering than those in plastic pots – but plants establish well in them, do not become pot-bound, and can be planted out without disturbing the roots.