Science for Kids: Overnight Crystal Garden

Any exploration of science for kids is not complete without growing some crystals….am I right? In fact, at the science fair this past year crystal growing projects were the project de jour, and I can understand why, growing a Crystal Garden has ranked pretty high up there on my list of fun science experiments since I myself was a kid!

Science for Kids: Learn how to grow crystals overnight using Epsom salts.Now one of the big drawbacks to many crystal growing projects is the time involved. I’ll be honest, I am not a patient woman and though I proselytize patience to my kids, I’m not a very good example of this virtue! So days of waiting for a crystal garden to grow pretty much sent this idea to the “someday” list. That is until I discovered Epsom salt crystals….leave them overnight and wake up to magic! Oh how much do I love thee Epsom Salt!

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To be fair, growing crystals using Epsom salt will not yield giant geodes bursting with color; Epsom salt crystals are small, delicate, and slivery. Instead of one or two mega crystals this science experiment for kids will give you hundreds of miniature crystals, they look a little bit like shards of glass and if you’re lucky you may get a few that look like snowflakes…We experimented quite a bit with this project to get good results and despite repeating the process exactly the same we had about a 70% success rate with crystal growth each batch we made. So plan on making 3-4 crystal gardens in case 1 or 2 don’t grow.  Another upside to making a few gardens at once is seeing how differently they grow, some crystal gardens were delicate and lacy, other were more rocky and gem like.  Be sure to make a bunch to delight you and the kids!

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Science for Kids: Overnight Crystal Garden



Science for Kids: Learn how to grow crystals overnight using Epsom salts.


  • Step One | Measure You will be using a ratio of 1:1 water to Epsom Salt for this project. Add 1 cup of Epsom salt to your jar/votive.  If you are working with larger jars feel free to add more salt but be sure to make a note of how much so you can add the same amount of water.
  • Step Two | Heat the Water Add 1 cup of water to a microwave safe bowl. Heat the water in the microwave for 45 seconds. Alternatively use very hot tap water and skip the microwave.
  • Step Three | Add Color If you are using color, add a dash of liquid watercolor to the water. Stir.
  • Step Four | Combine  Pour the water into the jar with the salt. Do this quickly so that the water is warm. Stir the salt and water for 1-2 minutes to dissolve the salt. We stirred for 2 minutes on most of our experiments.  Don’t worry if some of the salt remains undissolved at the bottom of the jar.

Science for Kids: Learn how to grow crystals overnight using Epsom salts.

  • Step Five | Cool Place the jar in the back of your refrigerator. Alternatively, quick cool the mixture for 10 minutes in the freezer and then move it to the refrigerator. Cooling in the freezer first yielded crystal growth in 90% of our experiments. We had just a slightly lower success rate going straight from mixing to the fridge.
  • Step Six | Let ’em Grow Leave the mixture overnight in the fridge.  Crystals may start forming in as little as 3 hours but we got the best results when we made the gardens in the evening and left them to sit undisturbed overnight Bonus: My daughter was excited to wake up and see how they had grown!

Science for Kids: Learn how to grow crystals overnight using Epsom salts.

  • Step Seven | Result Time Carefully pour out the extra liquid. It’s okay to leave a little liquid at the bottom of the jar. If you colored your water it will be hard to see if any crystals have grown until the excess liquid is removed. Clear water is easy to check.
  • Step Eight | Clean Use a wet paper towel to gently wipe away excess salt and color that may be on the upper portion of the jar. This will help you see the lovely crystal garden through the glass. Be careful not to damage any of your crystals!

You’re done! Hand the kids a magnifying glass for additional exploration. My kids really wanted to touch the crystals. That’s okay but let them know they are delicate and break easily.

Science for Kids: Learn how to grow crystals overnight using Epsom salts.


Science for kids is not without trial and error! Here are some tips I learned after repeating this experiment over 20 times…

  • There will be duds. I did this experiment many, many times, mixing up some of the variables, but the only constant was that I always had a few instances where the crystal would not grow. I’m not a chemist and I’m sure there is a reason why one mixture grew and another did not despite me thinking I had done the exact same experiment….So hedge your bets and make a few of these at one time. UPDATE: A few scientists have replied to this post and recommend dropping a grain of sand in each batch. Crystals need something to grow on and one little impurity in the water like grain of sand will should help ensure they have a place to nucleate.
  • Don’t overheat the water! I know it’s tempting to really heat that water up to make the salt dissolve, but all the experiments we did with really hot water, heated more than 45 seconds in the microwave, failed miserably. Trust me, DON’T DO IT!
  • Stir for at least one to two minutes! This is tough one for littler kids. My daughter was done stirring within a few seconds but you really need to get that water super saturated with salt to make the crystals grow. The less dissolved the salt is the smaller the crystals will be and worst case they may not grow at all.
  • Let them grow even longer in the fridge.  Leave them in the fridge longer than overnight and they should continue to grow. I left a few in the fridge for a over a week and the results got even better!
  • DO NOT let them sit in water at room temperature. Any crystals that have formed will deteriorate in the water at room temp. Once the crystals have formed and you want to preserve them you will need to pour out the water. I had some gorgeous crystals form in the fridge over the course of a week or so and I took them out and left them on the counter in the water. I came back the next morning to find they had flattened out. The one garden I poured the water out of remained stunning.
  • Make a Crystal Suncatcher with the leftover water!  

Make an overnight crystal garden from Epsom Salt!

Looks Like

Carlsbad Caverns. Have you been there? I was lucky enough to go there many, many years ago and it is as impressive and wondrous as you can imagine. I mean who wouldn’t be floored by descending into a bat filled cave to see huge stalactites and stalagmites? If you are ever in south eastern New Mexico you must make a trip there! For more local sightings, those of you in California can visit Mitchell Caverns in the Mojave Desert.

Well that was fun, right? Here’s a little something you can try with the leftover saturated water: Make Crystal Suncatchers:

Crystal suncatcher craft

Making Epsom Salt crystals is really simple and a great idea for a science fair project!

For more fun science experiment ideas for kids hop over here

20 Science Experiments for Kids. Many of these would be perfect for the science fair!

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Science for Kids: Learn how to grow crystals overnight using Epsom salts.


  1. says

    What a fun idea! I tried this last night and only one of my three jars grew the crystals. I wonder what the secret is? Like you, I thought I did each jar exactly the same way. I think it must have something to do with the heating of the water. We’re excited to try the suncatchers! Just stumbled across your blog yesterday and really like the concept and ideas! My kids and I look forward to trying more of your projects soon. Thanks!
    Holly recently posted…Craft Project: DIY Nail Polish Wash Necklaces & MagnetsMy Profile

    • Ana Dziengel says

      Hi Holly, I’m so glad you tried the experiment! I had some batches with more duds than successes and some batches where all of them grew! I wish I knew a chemist who might be able to illuminate me on why….I agree it must have something to do with the heating and cooling of the water. Did you try quick cooling a batch in the freezer for 5-10 minutes? That seemed to help get most of them growing. Also one more tip: Continue to let any that have crystallized grow in the fridge for at least a week. The crystals continue to grow over time! I left a few in the back of my fridge and checked on them one day and some of them had grown into even more impressive crystals. I’m going to write a follow-up on the post suggesting that too because some of the crystals were stunning!

      • says

        We did not keep ours in the refrigerator or cold. We did not pour off the water. We suspended a string and paper clip and set them on the table. As the water evaporated more crystals grew.

  2. Adriane says

    Do you have to keep them cold? Could my kids take them to school to show their class or would they turn to a watery substance like jello….? Thanks!

    • Ana Dziengel says

      Hi Adriane,
      Once the crystals have formed you can pour out the water and they don’t need to be chilled. Mine have been happily living in our kitchen for several weeks. They will harden even more over time and develop some white edges as they fully dry out. A couple tips: 1) Leave them in the fridge longer than overnight and they should continue to grow. I left a few in the fridge for a over a week and the results got even better! 2) DO NOT take them out and leave them in the water at room temp. They will deteriorate in the water at room temp. Hope that makes sense! 3) When pouring out the water save some for a Crystal Sucatcher.

      Take a pic when you have made your garden and post it on our FB page. I’d love to see how they turn out!
      Happy Experimenting!

    • Ana Dziengel says

      Thanks for stopping by Nate ! I tried plastic containers but did not get good results. You can try it but I do reccommend glass 🙂

    • Ana Dziengel says

      Hi Christy,
      That’s hard to say…..I microwaved mine for 45 seconds but also had luck with piping hot water from the tap. I wish I had a thermometer….I’d try heating water in the microwave for 30-45 seconds for a couple gardens, and the try and some hot tap water with a couple other gardens (inevitably some gardens grow and some don’t).
      Hope that helps!

  3. SpeedOrwinska says

    Why some were ‘duds:
    The secret is that you need a ‘nucleation site’ – a place where the crystals can get together and start forming a big structure. In chemistry labs they often put back in one tiny crystal at the end before leaving it to cool as this will act as a great place for the crystals to start growing from. Normally the crystals find some way to do this anyhow, either using a piece of dust or some other impurity in the water, or from using a scratch or bumpy surface on the glass vessel. In the cases where nothing happened, try adding a tiny epsom salt crystal into the solution and see if that gets it going?

    • Ana Dziengel says

      I have been trying to figure it out and this is such a great answer! I will try this and see if this does the trick 🙂 I really appreciate your feedback!

  4. says

    I tried this experiment and it was growing crystals in a couple of days but doesn’t it needs I sponge so it will stick to the crystals. My science teacher said I needed a sponge to have the crystals on it. Can I use the same procedures to make it with a sponge.

    • Ana Dziengel says

      Epsom crystals do not require a sponge to grow on but many other crystals do, like bluing and salt crystals 🙂

  5. zo says

    very very very very very very very very very very very very very very very very very very very very very cool im doing this for a scince fair project

  6. Gianna says

    Would I be able to take the crystal to school? Or would the crystal start to melt? Please answer! I have science project due!

  7. Holly says

    I think the reason you have duds is because you don’t have nucleation sites present in your super saturated solution. If you try again, throw in a few grains of sand or sugar to your cooled mix.
    I’m a material scientist… Theoretically this should work 🙂

    • Ana Dziengel says

      HI Holly, Another header said the same thing! I will have to try the experiment again with a few grains of sand mixed in. Thanks for deciphering that mystery for me!

  8. Roy and Lisa Woods says

    Thank you soooooo much, science expo soon, had a massive panic as my little girls science experiment wnt drastically wrong. Found this website, mums a hero now. Thanks

  9. Marilee Hird says

    I have found this works better with something to grow on and a supersaturated solution. The grandkids and I made Christmas ornaments with Epsom salts and pipe cleaners.

  10. JacksMom says

    I just found your site from frugalfun4boys and I’m hooked! Do you know of any early readers for science activities? My son has no interest in reading but loves science…I’m hoping to bribe him to read by experimenting along the way 😃

    • Ana Dziengel says

      Man how did I miss your lovely comment? Thank you for the kind words!!! I don’t know of any early readers but check out the site What Do We Do All Day. There are excellent book lists on it!

  11. Elizabeth says

    Hi I tried this last night I did a batch with food coloring and glitter and another batch just plain I hanged a string in one and yarn in the other I notice that the ones with the string grew and the ones with the yarn didn’t, I also tried this experiment with iodize salt (not recommended) and also the one with the string grew and the one in the yarn didn’t, what could be the reason ? If anybody knows please let me know

    • Ana Dziengel says

      Very interesting observations. I have heard that crystals grow better with an impurity in the saturated solution. Was the yarn cotton or synthetic?

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