Dishwasher Tablets

Dishwasher Tablets

🌱 A flexible dishwasher recipe that will save you time and money

 

Dishwashers clean differently to handwashing. They rely on alkaline conditions, heat, and water pressure to break down food residue and grease.

This recipe is built around that principle.

The two key ingredients are:

  • Washing soda, which provides alkalinity and helps break down grease
  • Sodium percarbonate, which releases oxygen in hot water to lift and remove food residue

Other ingredients can be added, but they’re optional rather than essential.

 

Powder or tablets - what’s the difference?

When I first started, I made tablets because that’s what we’re used to seeing commercially. I pressed the mix into ice cube trays to get that familiar tablet shape.

Over time, I realised there’s actually no need to do this. Leaving the mix as a powder:

  • Is quicker to make
  • Disperses better in the machine
  • Is easier to adjust
  • Avoids issues with crumbling or soft tablets

You can scoop the powder straight into the detergent drawer and get excellent results. Tablets still have their place - especially for other cleaning jobs — but for everyday dishwashing, powder is often the more practical option.

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Recipe & Instructions

Ingredients

  • 1 cup washing soda
  • 1 cup sodium percarbonate
  • 1–2 tablespoons coconut soap flakes (optional)
  • Essential oils (optional)
  • Water

Makes

Approximately 500g of powder - about 25 tablets 

Method: 

  1. Combine all dry ingredients in a mixing bowl, taking care not to inhale any dust.
  2. Add essential oils if using.
  3. Slowly add water a little at a time until the mixture resembles damp sand.
  4. Press firmly into silicone moulds or ice cube trays.
  5. Allow to dry for 24 hours or until fully hardened before removing and storing in an airtight container.

The mixture should hold together when pressed, but not feel wet.

How to use it

Use: 1 tablet per load

For best results:

  • Use a hot wash cycle
  • Pair with a rinse aid (vinegar or citric acid solution in the rinse compartment)

Important use notes

  • Use only on dishwasher-safe items
  • Do not use on aluminium
  • Hot water is essential to activate the percarbonate

How does this compare with commercial dishwasher tablets?
Both will clean your dishes. The difference is everything around that core function.

DIY dishwasher tablets are typically:

  • Cheaper – roughly 8–10 cents per load compared to 30–60 cents per load
  • Simpler – usually 2–4 functional ingredients instead of 30+
  • More versatile – the same ingredients can be used elsewhere around the home
  • Lower waste – with plastic-free and compostable packaging options

The cleaning outcome is similar; the system behind it is not.

Why are my tablets too soft or crumbly?
This usually comes down to water content. The mixture should feel like damp sand.

  • Too much water can cause tablets to puff, crack or soften
  • Too little water can cause them to crumble

If tablets do crumble, don’t worry. The crumbs are still perfectly usable, and nothing needs to be wasted.

Can I use vinegar or citric acid with this recipe?
Yes - but not in the same compartment.Vinegar and citric acid are acidic. Sodium percarbonate is alkaline. When combined directly, they neutralise each other. Use vinegar or a citric acid solution in the rinse aid compartment instead. This helps neutralise residue and improve glass clarity without interfering with the wash cycle.

Is this safe for septic or greywater systems?
This recipe is septic-safe. It doesn’t contain phosphates, chlorine or synthetic fragrances. Greywater use is more nuanced. While the ingredients are biodegradable, they are alkaline, which may not be ideal for garden reuse. If greywater diversion is important to you, this is worth considering..

My dishes came out cloudy - what should I do?
Cloudiness is usually a sign of mineral residue rather than poor cleaning. Try:

  • Using a rinse aid consistently
  • Reducing the amount of powder slightly
  • Avoiding overloading the machine
  • Cleaning your dishwasher if you’ve recently switched from commercial pods

Hot cycles generally give more reliable results than eco or short washes.
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