Hi Lacy, great question. This post needs an update to share what I have learned since we first made DIY rainbow building blocks. If you are concerned about young ones mouthing wooden blocks, use food coloring to dye them! Give it a try; it works great!

Thanks for the vote of approval Melissa!

They are super easy to make and turn out so beautifully!! I wrote this “How to” post so long ago it is in need of an update, and I hope to get to it soon. You can also use food coloring instead of liquid watercolors. It’s easy enough to mix them to make new colors, too. I hope that you enjoy making these rainbow-colored building blocks for your children!

Hi Jillian! Good questions!

No, we did not seal the blocks and yes, the watercolor paint might wash out a bit if they got wet. You can seal them with a white PVC glue like Mod Podge or use a beeswax polish, but we never really found the need. The Grimm rainbow blocks are left raw to keep the sensory nature of the wood intact for young fingers with developing sensory systems. The long answer is, you don’t need to protect them but if you want to make sure that they are sealed use Mod Podge or a Beeswax polish.