Switching to soap nuts is one of the simplest changes you can make to your laundry routine — but if you've never used them before, it's natural to have a few questions. How many do you use? Where do they go in the machine? How many times can you reuse them?

This guide walks you through everything step by step, so you can get a great wash first time and every time.

What you'll need

Using soap nuts requires just two things:

• 4–5 soap nut shells — half shells are fine, they don't need to be whole
• A cotton wash bag — this keeps the shells contained in the drum so they don't end up in your laundry. Every order from The Kind Wash includes reusable cotton wash bags.

That's it. No measuring cups, no risk of overdosing, no plastic caps to fiddle with.

Step-by-step: how to use soap nuts in a washing machine

1. Place 4–5 soap nut shells into the cotton wash bag. Don't overfill it — the shells need a little room so water can circulate through them and release the saponin.
2. Tie the wash bag securely. Make sure the drawstring is knotted so no shells escape into the drum during the cycle.
3. Add the wash bag directly to the drum with your laundry — not in the detergent drawer. The shells need to be in contact with the water to work.
4. Select your wash cycle as normal and start the machine. No other products are needed — no fabric softener, no additional detergent.
5. Remove the wash bag at the end of the cycle and leave it somewhere to air dry. Don't leave it sealed inside a damp machine as this can cause the shells to deteriorate faster.

What temperature should you wash at?

Soap nuts work best between 30°C and 60°C. Within this range they release saponin freely and clean effectively.

For washes below 30°C, the saponin release is slower because the cold water doesn't activate the shells as efficiently. The simple fix: before loading your machine, soak the wash bag in a cup of warm water for about 60 seconds, give it a gentle squeeze, then add it to the cold drum with your laundry. This kick-starts the saponin release and ensures you still get a good clean.

For washes at 60°C and above, soap nuts work well but the higher heat does use up the saponin more quickly, so you may get slightly fewer reuses per bag at these temperatures.

How many times can you reuse a wash bag of soap nuts?

Each bag of 4–5 shells can typically be reused for four to five washes before they're spent. After that, the shells will look visibly different — they'll be grey, soft, and papery rather than brown and firm. At this point they've released all their saponin and won't clean effectively anymore.

To keep track, some people leave the used wash bag on top of the machine and simply count the washes. Others do it by feel — give the shells a squeeze when wet, and if they feel thin and flimsy rather than plump, it's time to replace them.

The spent shells are fully compostable, so just empty them onto your compost heap or into your food waste bin.

Do soap nuts work in front-loading and top-loading machines?

Yes — soap nuts work in both front-loading and top-loading washing machines. The wash bag goes directly into the drum in both cases. They're also suitable for high-efficiency (HE) machines, which is worth knowing as many eco-certified detergents aren't.

Can you use soap nuts for every type of laundry?

Soap nuts are suitable for almost all fabric types and laundry categories:

• Everyday cottons and synthetics — works perfectly at standard wash temperatures
• Colours — soap nuts won't fade or bleed colours over time
• Delicates, wool, and silk — the gentle saponin formula is safe for hand-wash fabrics at cool temperatures
• Baby clothes and bedding — ideal, as there are no chemicals, dyes, or fragrances to irritate sensitive skin
• Towels and bedding — works well, though very heavily soiled items may benefit from a pre-soak

For heavily soiled items — workwear, sports kit, or anything with stubborn stains — pre-treat the stain directly with a natural stain remover before washing for the best results.

Do you need fabric softener with soap nuts?

No — and this is one of the things people notice most when they switch. Soap nuts leave clothes naturally soft without any additional fabric softener. This is because saponin doesn't leave a residue on fabric fibres the way synthetic detergents do, so your clothes feel cleaner and softer without the need for extra products.

If you want to add a natural fragrance to your laundry, add a couple of drops of your favourite essential oil (lavender and tea tree are popular choices) either directly to the drum or onto a set of wool dryer balls.

Tips for getting the most out of your soap nuts

• Store unused soap nuts in a cool, dry place — a sealed bag or jar works well. Avoid damp environments as moisture will cause them to start releasing saponin prematurely.
• In hard water areas, you may find you need 5–6 shells rather than 4–5 to get the same cleaning performance, as minerals in hard water can slightly reduce saponin effectiveness.
• You can use the spent shells to make a liquid soap nut solution for other household cleaning tasks before composting them — a great way to get extra value before they go in the bin.

Ready to get started?

If you haven't tried soap nuts yet, the easiest way to start is with our trial pack — just £1.99 for a 20g sample with a wash bag, enough for around five washes.

Try the soap nuts trial pack — £1.99 →

Already convinced? Our 1kg bag gives you up to 300 washes and is the most popular choice for households making the switch to natural laundry.

Shop the 1kg Soap Nuts — £13.95 →