Skip to main content
40% off

Archive Sale opens 27 October

Sign up

Removing green algae in winter: the best method

Removing green algae in winter calls for an adapted approach. Read what you need to keep in mind.

Wooden deck half cleaned, with green algae still visible

What you need for this tutorial;

Removing green algae in winter may seem like a challenge, but with the right approach it is very doable. The damp, cold winter months give moss and algae the chance to grow on your wooden deck, terrace or garden furniture. This makes surfaces slippery and unattractive. Fortunately, there are proven methods to get your garden clean again. In this article, you will read how to remove green algae without damaging the surface, and how to prevent it from coming back quickly.

Video: Removing green algae in winter

In this video you will see how to remove green algae from wood.

Groene aanslag verwijderen: hoe verwijder ik groene aanslag?

Groene aanslag verwijderen: hoe verwijder ik groene aanslag?

Step-by-step plan: removing green algae in winter

Green algae can build up quickly in the winter months, but with this proven method you can remove it in no time:

1

Choose a suitable cleaner

An effective cleaner is essential for a thorough clean. Osmo Terrasreiniger removes green algae without damaging the surface, so your wood lasts longer.

Wooden bench with green algae
2

Dilute the Osmo Terrasreiniger

The right dilution depends on how dirty the surface is:

Light green algae: 1 part Terrasreiniger to 25 parts water

Heavy green algae: 1 part Terrasreiniger to 1 part water

Pouring Terrasreiniger into a bucket
3

Scrub the surface thoroughly

Use an Osmo patio brush to remove the algae. Work in the direction of the wood grain.

Cleaning a wooden deck with green algae
4

Let the product work

Give the product 10 to 15 minutes to work, so the green algae loosens and comes away from the surface.

Wooden steps with green algae
10-15 minutes
5

Rinse with clean water

Use a garden hose or a bucket of water. Do not use a pressure washer, as it can damage the surface and cause green algae to return more quickly.

Rinsing a wooden deck
6

Let the surface dry thoroughly

Prevent new green algae by making sure water drains away well, so it does not pool and moss and algae have less chance to grow.

Wooden deck in the sun

Benefits of Osmo Terrasreiniger

✔ Powerful cleaning without damaging the surface
✔ Economical: 1 liter of cleaner is enough for 30 to 100 m²
✔ Suitable for wooden decks, fences and garden furniture

Tips to prevent green algae

  • Make sure water drains away well, so it does not pool on your tiles or deck.
  • Place your deck in a sunny spot, because sunlight slows the growth of moss and algae.
  • Do not use vinegar, salt or chlorine, as these products can damage the surface.
  • Treat your deck with a protective coat, such as Osmo Terras-Olie for wood or Osmo Steen en Terracotta Olie for stone, so green algae has less chance to grow.

Supplies

Besides these products, you will also need a bucket of water or a garden hose.

Preventing green algae from coming back

Want to prevent green algae from coming back quickly? Treat your deck with a protective coat after cleaning:

Wooden surfaces (vertical wood): Osmo UV-Beschermingsolie
Wooden surfaces (horizontal wood, such as decks): Osmo Terras-Olie
Tiles and stone surfaces: Osmo Steen en Terracotta Olie

Let the surface dry for at least 24 hours before applying the protective coat.

Maintenance advice

  • Clean your deck at least twice a year to remove green algae.
  • Make sure water drains away well, so there is no standing water.
  • Use Osmo Terrasreiniger for an effective, gentle clean of your wooden surfaces without damaging them.

Frequently asked questions

This tutorial belongs to

What you need for this tutorial;

We're happy to help

Looking for DIY advice or have a technical question?

Need DIY help?

Find your project and read the step-by-step guide.

Technical question?

Get advice from a technical specialist.