How to Grow Salt Crystals

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How to Grow Salt Crystals


Making crystals out of either salt or sugar is a fun project that the whole family can get involved in. While not difficult, it is time consuming – but the end result always pays off. Although the salt crystals will not be edible like sugar crystals are, they look just as amazing and are the perfect way to teach kids about the process by which all crystals form. Also, no two crystals will look the same, as every time you make salt crystals you will come out with something entirely different from what you got last time.


The materials used in making salt crystals are roughly the same as those that are necessary for sugar crystals – just substitute salt for sugar. You will need one cup of water, several cups of salt, and food coloring so that your crystals can look exactly how you want them to. You will also need various other materials to help the crystals grow. These other materials include a glass jar, string, a paper clip, and a pencil. Note that you can substitute the string for dental floss, the paper clip for any metallic object that can help crystals grow, and the pencil for a Popsicle stick. You should also set aside some petroleum jelly to keep the crystals where you want them.


Start by bringing your cup of water to a boil. A microwave is perfect for quickly boiling about a cup of water. When the water has boiled, you pour it straight into the glass jar.

Adding Salt

Quickly begin adding the salt to the boiling water in the glass jar. Do not add it all at once though – only a teaspoon at a time until the water is saturated with salt. This is the most important step if you want the project to be successful, so do not rush. Stir vigorously after each additional teaspoon so that the salt can mix thoroughly. Reheat the water again if it starts to cool too much. You will know you are done when the salt starts to collect along the bottom of the jar, indicating that the solution is over its saturation point.

Coloring the Crystals

If you want colored crystals, you can add a few drops of food coloring to the salt water solution. Usually a couple of drops are all that you need to produce beautiful iridescent colors. You can also mix colors to create vibrant purples and other colors.

Creating a Growing Surface

Next, take your string and tie it to the middle of the pencil you set aside earlier. The string will later become a surface for the crystals to latch on to. Tie the other end of the string to your paper clip to create a starting point for the growth of the crystals. Also, if you mixed everything together properly at this point, your crystals will form not just on the string and paper clip – but on the entire jar itself. If you do not want crystals all over your glass jar, you can rub some petroleum jelly (like Vaseline) just above the water line on the inside of your jar.

Time to Wait

Once your string is securely tied, place the pencil on top of the glass jar so that the string can dangle inside the jar much like a fishing line. The paper clip should be very close to the bottom of the jar – but do not let it touch. Set the jar somewhere where it can sit undisturbed for several days. If everything is done correctly, you will see cube shaped crystals forming after about 24 hours. You may also want to place a paper towel on top of the jar to keep dust and debris from contaminating your salt crystals.

Growing Salt Crystals Images



  1. maryo said,

    on February 18th, 2010 at 7:23 pm

    Question what kind of string do you use?
    Can it be yarn? I was thinking multi-colored

  2. Science Girl said,

    on December 5th, 2009 at 12:33 pm

    Do you guys think this will be good for a science project?

  3. andy said,

    on November 11th, 2009 at 6:54 pm

    i hope they grow quickly….its pretty exeptonial!

  4. Ashleigh said,

    on June 2nd, 2009 at 9:43 pm

    My teacher says that we don’t need the pencil part. Is this true?

  5. Joanna said,

    on May 3rd, 2009 at 6:49 pm

    I like the way u think but i still have one question,… WHY DO CRYSTALS FORM WHEN USING SALT AND BOILED WATER?

  6. Alicia said,

    on April 24th, 2009 at 7:26 am

    i dont think that the crystals will grow within one day

  7. superteacher said,

    on March 18th, 2009 at 4:43 pm

    Well…my daughter and I just completed the growing crystal set-up. I am hoping to have crystals by tomorrow! I am confident! The directions were easy for us to follow. Thanks!