Removing green growth from an awning
treat algae and moss according to the fabric
A green film on the fabric of your shade can usually be removed with simple means. Which product you may use depends on the weave: Agora and Sunbrella tolerate a diluted bleach solution, Dralon, Olefin and polyester do not. Here you can read what suits your fabric, how to proceed step by step and how to prevent new growth.
Green growth, algae and moss sit on the surface of the fabric like mildew. If you want to remove algae from an awning, the way the weave is dyed decides which product to use. You will find all other topics on your awning in the awning guide.
- First brush off loose growth and moss dry with a soft brush.
- Agora: apply a 1:20 bleach solution, leave it to work briefly, rinse thoroughly with clear water, then wash again with a 1:20 washing-up liquid solution.
- Dralon, Olefin and polyester such as Polysun: no bleach, only a 1:20 washing-up liquid solution and a soft brush.
- Lukewarm water, 30 degrees at most. No pressure washer, no abrasive cleaners.
- Leave to air-dry in the shade, not in full sun.
- Park the bundle of fabric of the rope tension awning under the roof, so that it does not lie exposed to the weather.
Which fabric tolerates bleach?
The dyeing is what matters. With solution-dyed acrylic, the colour is already in the liquid mass the fibre is made from, so every fibre is dyed right through to the core. With conventionally dyed acrylic such as Dralon, the colour is applied from outside. The panels of our made-to-measure rope tension awning are available in Dralon, Polysun, Agora and Olefin. You can read which awning designs there are under what are awnings. You can also get our outdoor fabrics as fabric by the metre.
| Fabric | Fibre and dyeing | Bleach 1:20 | Against green growth |
|---|---|---|---|
| Agora | Solution-dyed acrylic | Allowed | Apply 1:20 bleach solution, leave to work briefly, rinse clear, wash again with 1:20 washing-up liquid solution |
| Dralon | Conventionally dyed acrylic | No, not even diluted | 1:20 washing-up liquid solution with a soft brush; for very stubborn growth, diluted 3 % hydrogen peroxide after a test on an inconspicuous spot |
| Polysun | Polyester | False | Washing-up liquid solution by hand, 30 degrees at most |
| Olefin | Polypropylene | False | Neutral soap solution with a soft cloth in gentle circular movements, rinse clear |
| Fabric unknown | Cannot be identified with certainty | Not without a test | Stick to the 1:20 washing-up liquid solution, use bleach only if the fabric is definitely Agora |
Cleaning green growth off an awning: step by step
Make the fabric accessible
Extend the awning so that the fabric lies smooth, or make it easy to reach in another way.
Brush off dry
Remove loose growth, moss and leaves dry with a soft brush or with a vacuum cleaner and upholstery nozzle.
Mix the solution to suit the fabric
For Agora, mix 1 part bleach to 20 parts water. For Dralon, Olefin and Polysun, use 1 part washing-up liquid to 20 parts lukewarm water, 30 degrees at most.
Apply and leave to work
Apply the solution with a sponge, soft cloth or soft brush in circular movements. Leave the bleach solution to work briefly.
Rinse clear and wash again
Rinse thoroughly with clear water. After the bleach solution, wash again with a 1:20 washing-up liquid solution and rinse clear once more. Otherwise soap residue in the weave attracts new dirt.
Dry in the shade
Leave the fabric to air-dry in the shade. Damp fabric in full sun can develop water marks.
Household remedies for verdigris on an awning
Many people say verdigris when the fabric turns green. Real verdigris forms on copper and brass, and on an awning what is usually meant is a coating of algae. So if you want to remove verdigris from an awning, you treat it like algae. To remove green growth from an awning with household remedies, you need only a few things.
Washing-up liquid 1:20
1 part washing-up liquid to 20 parts lukewarm water, 30 degrees at most. This solution suits every awning fabric.
Bleach 1:20 only for Agora
Household bleach, 1 part to 20 parts water, does not attack the fibre of solution-dyed acrylic, which is dyed right through. More on the fabric under Agora Liso.
Hydrogen peroxide for Dralon
For very stubborn growth on Dralon, you can try diluted 3 % hydrogen peroxide. Test it first on an inconspicuous spot. More on the fabric under Dralon.
Vinegar, bicarbonate of soda, baking powder
No care instructions from the fabric manufacturers mention these products. Abrasive and solvent-based products are ruled out. If in doubt, stick to washing-up liquid.
A soft brush is enough
A soft brush, a sponge or a soft cloth is enough. You do not need a special green growth remover for the awning.
Removing moss from an awning
You treat moss like green growth and algae, because it also sits on the surface of the fabric. Brush loose moss off dry first, before water presses it into the weave. Then treat the remains with the solution your fabric tolerates. If moss grows on an awning, the fabric is often damp for a long time.
Brush dry first
Soft brush or vacuum cleaner with upholstery nozzle, without water. This removes most of the moss.
Treat the remains according to the fabric
For Agora with a 1:20 bleach solution and a second wash, for Dralon, Olefin and Polysun with a 1:20 washing-up liquid solution. Then rinse clear and dry in the shade.
Check the cause
Check where the fabric lies when it is retracted. The bundle of fabric belongs under a roof and should not lie exposed to the weather.
What harms awning fabric
For polyester and polypropylene, the manufacturers' instructions rule out pressure washers, and on coated fabrics they loosen the coating. Even on acrylic, a brush and sponge are enough.
On Dralon, even diluted bleach can fade the colour or make it blotchy. Olefin and polyester do not tolerate bleach either.
Hot water can impair the water-repellent finish. Lukewarm is enough.
No dry cleaning, no petrol, no solvents and no abrasive cleaners.
With the acrylic panels of the rope tension awning, every wash washes more of the protective finish out, and the fabric then gets dirty faster. So treat the growth in a targeted way instead of often washing the whole panel.
You can read whether a waterproofing spray is suitable for your fabric under waterproofing an awning.
So the green growth does not come back
If you have had to remove algae from your awning, you do not want to see it again next year. Green growth grows where dirt lies and the fabric stays damp for a long time, for example under trees in the garden.
Park the bundle of fabric under the roof
On the rope tension awning, the fabric pushes together into a bundle when you retract it. Park it under the roof the awning is mounted under. The bundle should not lie exposed to the weather.
Store clean and dry
In autumn, store the fabric only when clean and dry, and it is better to let it air-dry for a day longer. Moisture is the main cause of mildew in stored fabric. Do not store it directly on a bare concrete floor.
Brush off in spring
Brush or vacuum the fabric thoroughly once before the season and treat stains from storage straight away. Fresh growth comes out more easily than old.
Other stains, other page
Mildew spots, mould and bird droppings have their own rules: removing mildew spots from an awning. Normal cleaning without growth is covered under cleaning an awning.
Green growth on a shade sail
The same fabric rules apply to a shade sail. You can read more under cleaning a shade sail.
When the fabric is at its end
If the fabric has become brittle after many years, cleaning is often no longer worthwhile. You can read how a new cover gets onto the frame under re-covering an awning.
Frequently Asked Questions
Sources
Last reviewed: 23.10.2026 · Reviewer: Germes-Team
Not sure which fabric your awning is made of?
Send us a photo of the fabric and of the growth. We will tell you which product the fabric tolerates and what you had better avoid.