DIY Galaxy Ice Dyed Onesie

I stumbled across the concept of dyeing fabric last year when I was deciding whether to sell my stone gray Lillebaby carrier.

It wasn’t getting much love and had a ball point pen mark on the front. On Facebook I saw a gray baby carrier that had been dyed to look like a gorgeous galaxy and I NEEDED to know how it was done.

I joined the Dyed Baby Carriers group on Facebook and learned way more about fabric dyeing than I expected thanks to fantastic tutorials from Valene with Starry Skies Tie Dyes

Now I know why every t-shirt I tie-dyed at Girl Scout camp as a kid faded so much after washing… we always used really inexpensive Rit dye.

Rit dye isn’t colorfast. To get the dye to be permanent, you have to use the good stuff and you have to pre-treat the fabric. When done right, the dye is permanent and safe for babies. Apparently there’s some science involved.

Before I dove into dyeing my baby carrier, I dyed a few muslin swaddling blankets. They turned out so awesome that I was hooked.

I’ve since dyed three Lillebaby carriers, a few more swaddling blankets, some t-shirts for my kids, and a linen ring sling. 

This post is about a onesie I galaxy dyed for my sister’s baby shower. The magic and randomness of ice dyeing means the results will look different on every item you dye. These steps can be applied to almost anything you’re planning to dye.

What You’ll Need:

  • 100% cotton onesie (or a blend of all-natural fibers; bamboo, hemp, linen, etc. Cannot be synthetic/polyester.)
  • soda ash
  • fiber reactive dye in however many colors you want (the best dyes are from Dharma and Custom Colours. Dylon is supposed to be good too and you can buy it at many craft stores like JoAnn’s)
  • aluminum foil (optional)
  • a drying rack (do not use it with food after it’s been in contact with dye)
  • a container to catch water and dye as the ice melts
  • nitrile or latex gloves
  • safety mask (N95 Respirator is recommended)
  • blue Dawn dish soap
  • 2-3 pounds of ice (more if you’re dyeing a larger item)
  • white fabric paint and a skinny paintbrush


1. Wash and dry your onesie. No fabric softeners. Some websites recommend washing it with blue Dawn dish soap, but it freaks out my HE washing machine. Regular washing with our “free & clear” detergent worked fine for me.

2. Put on your gloves and mix 1 cup of soda ash with 1 gallon of hot water in a tub (if you don’t need a whole gallon, use half a cup and half a gallon). Let the onesie soak for at least 20 minutes. Longer is fine, I ended up soaking this overnight.

Soda ash is 100% sodium carbonate (not baking soda!). You can buy it online or pick it up at hardware stores in the section that sells pool supplies.

There it can be labeled as pH-Up. Sometimes arts & craft stores will carry it. Soda ash changes the pH of the fabric so the dye can bond with the fibers.

It’s a REALLY important step that you don’t want to skip. Skipping this step will result in much less vibrant colors.

3. Wring out your onesie to get as much of the water out as possible, but don’t let it dry completely. Throwing it in the washing machine and running a spin cycle works like a charm. Just a spin cycle, not a rinse too! The soda ash solution will not harm your washing machine.

4. Lay the onesie on your drying rack with a tub underneath. 

5. When working with the dye in a powder form, wear a mask and gloves. This is important!!

6. Pile some ice on the onesie, making sure there is some all over. If you’re having trouble with ice falling through your drying rack, you can create some little walls with aluminum foil.

7. With a spoon, sprinkle dye in small sections, taking care not to put colors next to each other that would turn to mud when blended.

When thinking of the color wheel, colors that are opposites will blend and look muddy (red/green, blue/orange, yellow/purple).

If you want your onesie to still have a little white showing, use only a little dye. If you want little to no white, then use a little more dye. I was sprinkling maybe a teaspoon of each color.

8. Put the whole thing in a spot where it won’t get disturbed by little ones and let the ice melt. It could take a few hours or it could take a whole day.

It’ll vary on how much ice you used and how warm your room is. Mine took about 8 hours to melt completely. In the backyard on a warm day, it’ll melt pretty quickly.

9. When the ice is really starting to melt, sprinkle a little soda ash over the ice to compensate for the soda ash that is lost as the ice melts through the fabric.

If you see any spots where the dye isn’t in contact with ice, add more ice. I added a few more pieces of ice at this step, especially along the edges.

10. When the last piece of ice has melted, start the “batching” clock. Cover the whole gig with a plastic trash bag.

Close it as tightly as you can so it stays damp and leave the whole thing in a warm spot, between 70° and 120° F for 24-36 hours.

This time spent in a warm environment (called batching) is when the dye chemically bonds to the fibers. You can put it outside in the sun on a warm day, in a hot car, or in a warm room close to a heating vent. I’ve heard some wrap it in an electric blanket. Just make sure the bag is securely closed! 

11. When the onesie is done batching, rinse it under cold water until the water runs clear. I usually do a few soaks in cold water in a plastic tub. Rinsing always takes longer than I expect.

12. When the water runs clear (mostly), wash it in hot water with a drop of blue Dawn dish soap. The Dawn soap helps loosen any bits of dye that didn’t bond with the fabric. Sometimes I need to do this a couple of times to truly loosen all of the extra dye. 

13. Throw in the dryer and then admire the work you did!!

14. To paint the stars, I use Tulip Soft Fabric Paint (available at most craft stores). I load up a #2 or #4 sized round brush with white paint that’s been mixed with a little water and then tap the brush over the onesie to get lots of tiny drops.

Some use a skinny paintbrush and paint each star, some use a toothpick, or run their fingernail over an old toothbrush.

There are lots of methods to try. I have also been known to mix in a little glow-in-the-dark fabric paint with the white. Let the paint dry for 24 hours and it’s permanent.

These are the colors I used on the onesie in the photos: Dharma Fiber Reactive Dyes in Glacier Blue, Chinese Red, Jade Green, and Deep Space.

Is this a lot to go through to simply dye a onesie? Sure!! But you may find yourself hooked and looking for more projects to dye. How about a couple of muslin swaddling blankets? Pillowcases? PJs?

Got anything you’d like to try this on?? 

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