How to Remove Green Algae Stains from Clothes

Green algae is alive – so you have to kill it, not just wipe it

Green algae growth isn't an ordinary stain but a living colony of algae and mildew that settles on textiles that never get to dry. That's why wiping it with a cloth doesn't help – you just move the growth around, and it blooms again the moment it's damp. To get rid of the green you have to kill the microbes and then remove the film itself. Note the difference between stain and smell: if it's mainly a musty, cellar-like odour from the garment, it's the smell you're after, not the green film.

Brush off the loose growth first – outdoors

Take the garment outside before you do anything else. Shake and brush off as much of the green, dry film as you can while it's dry – wet spreads more easily, and you avoid breathing spores indoors. Use a soft brush and put what you remove straight in the bin. Only once the loose material is gone should you bring the garment in for treatment.

How to wash the green algae out

Now kill the growth and lift the colour. Two products cover most cases: colour-safe oxygen bleach (percarbonate) for both white and coloured, or white vinegar for a milder, gentle treatment on lighter growth. Choose by fabric and how ingrained it is.

1. Mix oxygen bleach in warm water (as warm as the care label allows), or make a solution of white vinegar and warm water for delicate garments.
2. Soak the garment for 30–60 minutes, so the product has time to kill the algae and loosen the film.
3. Then wash the garment as warm as the care label allows, ideally with an extra dose of oxygen product in the wash.
4. Check the green is completely gone BEFORE you dry it – heat can set any remainder permanently.
5. If a little still remains, repeat the soak instead of scrubbing hard.

Dry fully – ideally in the sun

Drying isn't an endpoint but part of the treatment itself. Dry the garment right through, ideally outdoors in the sun: sunlight (UV) helps finish off remaining spores and at the same time bleaches away a faint green shadow. Most important of all is that the garment is completely dry before you put it away – the smallest bit of leftover moisture is all green algae needs to return.

White canvas, tents and delicate fabrics

Different fabrics tolerate different treatment, so adapt to the garment – and always test the product on a hidden spot first.

• White cotton and canvas (tents, awnings): take a stronger oxygen soak, and only if the care label allows, diluted chlorine bleach – never on coloured or delicate textiles.
• Technical and proofed fabric: killing the algae can weaken the water-repellent finish, so the garment may need re-proofing afterwards.
• Wool and silk: stick to weak, diluted oxygen bleach in cool water, never chlorine – and test first.
• If you're unsure of the fabric, choose the gentlest product or send the garment in.

When should you send the garment to us?

A lot of green algae on ordinary, washable garments is a straightforward home job – we'll say that honestly. But if the garment is dry-clean only, is delicate wool or silk, is technical or proofed, or the growth sits deep and won't shift, you can send it to us. We treat the growth according to the fibre and its care label, without cooking the stain in or weakening the fabric. If the garment has also taken damage or needs re-proofing afterwards, we can handle it in the same round. You order online, and you see the price before you order.

Frequently asked questions