How to Use Mrs. Stewart's Laundry Bluing in a Salt Crystal Garden

Written by siva stephens
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How to Use Mrs. Stewart's Laundry Bluing in a Salt Crystal Garden
Make crystals "bloom" in a salt-crystal garden. (Jupiterimages/ Images)

Mrs. Stewart's Laundry Bluing is a liquid that, when added to the rinse water after washing, makes white fabric appear whiter. It consists mainly of very small particles of blue iron suspended in water. In a salt garden, these particles serve as "seeds" around which the salt crystals will grow, in much the same way as a pearl will form around a speck of sand. The addition of the bluing to the garden makes the crystals form as "blooms" instead of sheets.

Skill level:

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Things you need

  • Shallow, non-metal container such as a glass pie plate
  • Charcoal briquette pieces, clay pot shards, sponge or other porous material
  • Plastic cup
  • Plastic spoon
  • 2 tbsp non-iodised salt
  • 4 tbsp water
  • Food colouring (optional)
  • 2 tbsp liquid bluing
  • 2 tbsp household ammonia

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  1. 1

    Soak the porous material with water until it is saturated. Cover the bottom of the plate with pieces of this substrate. Mix 2 tbsp of non-iodised salt into 4 tbsp.of water and stir until as much of the salt as possible is dissolved. Add 2 tbsp of bluing and 2 tbsp.of household ammonia to the mixture and stir well.

  2. 2

    Pour the mixture over the porous material, including any undissolved salt crystals. Add a few drops of food colouring in some areas if you want coloured "blooms." Leave the dish undisturbed for several hours.

  3. 3

    Keep your salt crystal garden growing indefinitely by sprinkling 2 tbsp of non-iodised salt over the garden the day after you set it up. Periodically add more of the salt/water/bluing/ammonia mixture whenever you want more blooms in your garden. Pour the solution into the bottom of the dish rather than over the garden to avoid dissolving the established crystals.

Tips and warnings

  • It can take up to two weeks for a garden to bloom in an especially humid environment.
  • Scientifically, the porous material of the substrate soaks up the salt/water/bluing/ammonia solution using capillary action, which draws the solution up through the substrate material. Ammonia causes the solution to evaporate more quickly in open air, and as the water evaporates the iron particles in the bluing can no longer remain in suspension. They are deposited on the surface of the substrate and, as the water continues to evaporate, the suspended salt re-crystallises around the iron particles. Capillary action pulls the remaining solution through both the substrate and previously-deposited crystals, so the crystal formations appear to "bloom."
  • Bluing will stain clothes, skin and other surfaces, so wear old clothes and use disposable utensils for this experiment.
  • Supervise children closely when using any chemical products.

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