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Ready for a festive Christmas science experiment that looks like pure holiday magic? Growing a Crystal Christmas Tree is a hands-on project that kids love watching—crystals form right on your cardboard tree overnight! If you’ve ever seen the store-bought “magic crystal trees,” this is a DIY version you can make at home with a few simple ingredients.

It’s beautiful, fast, and a perfect Christmas STEM activity for classrooms, homeschool, or holiday break.

Safety Note

This experiment uses strong household chemicals (ammonia and laundry bluing).
Adult supervision is required for mixing and handling the solution.
Once the solution is prepared, kids can safely help with all the other steps.

Supplies to Grow a Crystal Christmas Tree

• Cardboard- we used the back piece of some old notebooks.
• Laundry Bluing– a solution used in laundry to make whites look brighter, can be found in laundry sections of the grocery store.
• Ammonia
• Table Salt
• Small Dishes– we used plastic petri dishes
• Food Coloring (optional, but more fun!)

How to Make a Crystal Tree

1. Cut out your cardboard tree shapes

Draw a simple tree shape and cut out three identical trees. A thin cardboard works best—it absorbs liquid more quickly.

Tip: We tried snowmen, too. Trees grow better than snowmen because branches create more edges where crystals can form.

Make sure the base of each tree is wide enough to stand in your dish.

2. Cut slits so the trees can fit together

• On two trees, cut a slit from the top halfway down.

• On the third tree, cut a slit from the bottom halfway up.

Keep the slits narrow so the pieces fit snugly. Fold the two “top-slit” pieces slightly outward at a 90° angle—this helps the tree stand.

Fit all three pieces together to form a 3D tree and place it in your dish.

3. Add color to the edges (optional but so pretty!)

Paint or dab food coloring around the cut edges of the cardboard.
Kids can use:

• Markers

• Liquid watercolors

• Food coloring (very vibrant!)

The color travels up the cardboard and creates naturally multicolored crystals.

Make the Crystal Tree Growing Solution

Mix the following in a small cup:

• 2 Tbsp table salt

• 2 Tbsp warm water

• 2 Tbsp laundry bluing

• 1 Tbsp ammonia

• Several drops of food coloring (optional)

Stir until the salt dissolves.

Grow Your Crystal Tree!

Pour the solution into the bottom of your dish, making sure the tree sits directly in it.

Do not move the dish once the solution is added.

• Check after a few hours—you’ll already see crystals forming.

• Leave overnight for fullest growth.

The next day, your tree should be covered in soft, fluffy crystals!

Note: These crystals are fragile and will flake if touched. They’re meant to be admired, not handled.

How Does the Crystal Christmas Tree Work? (Kid-Friendly Science)

This experiment demonstrates:

Capillary Action

The liquid mixture travels up the cardboard fibers the same way a real tree pulls water through its roots.

Evaporation

Ammonia speeds up evaporation. As the liquid evaporates, it leaves behind the solid ingredients.

Crystal Formation

Salt and bluing combine to form crystals where the cardboard fibers meet the air.
Bluing is a colloid, meaning it blends with water but does not fully dissolve.
As the water evaporates, the salt and bluing bind together and crystallize—creating the snowy, fluffy effect.

This makes a fantastic December science lesson!

Christmas Science Extensions & Variations

• Try a snowflake shape instead of a tree.

• Use multiple colors for rainbow crystals.

• Make a crystal forest by placing several trees in one dish.

• Compare salt-only crystals vs crystals made with bluing + salt.

• Add a simple observation journal for kids.

Try Some More FUN Christmas Science Activities:

Christmas STEM: Rudolph Pipe Cleaner Circuit

Christmas Candy Cane Science Experiment (Diffusion Activity for Kids)

Christmas STEM: Poinsettia Ph Experiment

Soft Circuit Christmas Ornament: Christmas STEAM