Join the RHS today and support our charitable work
Free personalised gardening advice
RHS members get reduced ticket prices
RHS members get free access to RHS Gardens
Free entry to RHS members at selected times »
Reduced prices on RHS Garden courses and workshops
020 3176 5800
Mon – Fri | 9am – 5pm
Help us achieve our goals
Join the RHS today and support our charity
Green growths such as algae, liverworts and moss can accumulate on the glazing and surfaces of greenhouses, where they are unsightly and cut out light. They can be controlled by improving hygiene and ventilation.
Algae and moss in a greenhouse. Credit: RHS Advisory
The build up of moss and algae on greenhouse glazing cuts out precious light from getting to the plants. It can also be problematic on greenhouse flooring and staging.
Algae: A green film or powdery deposit is typical of algae on greenhouse glazing.
Liverworts: Liverworts usually have a green, flattened, plate-like body and no leaves. A common example is Marchantia, which is often topped with umbrella-like sexual organs.
Moss: Moss that grows on glazing bars and on the surface of compost is usually cushion-like.
Algae, liverworts and moss on internal greenhouse surfaces may indicate a need for increased ventilation and more careful watering.
Where possible, increase ventilation in the greenhouse, especially in winter months.
Water carefully to avoid puddles of standing water.
Thorough greenhouse cleaning should be carried out at least once each year, usually best done in late winter to early spring. Dislodge moss and algae from between glazing panels with a flexible plastic plant label.
There are several products available to remove moss and algae from hard surfaces in greenhouses, including the floor, staging and glazing.
Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.
Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see section 2b)
Algae, lichens, liverworts and moss
Algae, liverworts and moss on borders and containers
Algae, lichens, liverworts and moss on hard surfaces
the RHS today and get 12 months for the price of 9
RHS members can get exclusive individual advice from the RHS Gardening Advice team.
We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.