Making 9,000 Grow Spheres




Introduction: Making 9,000 Grow Spheres

About: Science educator, museum coordinator, and general wise-guy

The goal was to make 90 centerpieces that would contain these amazing grow spheres that would be centerpieces for a cocktail-esque fundraiser event.

Step 1: Find a Good Fit

Pick out a groovy piece of glassware to display your spheres. Roughly 90-100 jumbo grow spheres fit nicely into one of our large martini glasses. For simplicity we rounded to 100.

Step 2: A Little Math

We then counted 100 dry grow spheres and found their mass to be 5.5 grams.


100 grow spheres = 5.5 grams

[90] * 100 grow spheres = [90] * 5.5 grams

9000 grow spheres = 495 grams


For simplicity ~500 grams of dry grow spheres will make ~9000 grow spheres.

Step 3: No Scale?

If you don't have a scale a helpful measurement is that one standard styrofoam coffee cup will hold about 175 grams of jumbo grow spheres.

Step 4: Food Coloring

We went to GFS and picked out some bulk food coloring. Those little bottles you get at the local grocery store are not going to cut it.

Getting the color you want is somewhat challenging since the concentrated food coloring doesn't necessarily reflect the true color. Our goal was to make some blue, orange, and florescent yellow spheres. Blue was easy. We just added a half bottle of food coloring to a small dish and let them soak.

Making orange was slightly more difficult because food coloring only comes in yellow (or eggshell) and red. We started by mixing 400 mL of each together hoping a 50/50 mix would give us orange but ended up needing to add another 300 mL of yellow to lighten it up; in my opinion they were still to dark. My advice is start with a lot of yellow and slowly add red until you get the orange color you want.

Step 5: Florescein

We have access to some raw florescein from our chemical lab to make the yellow grow spheres. You can order it from most chemical supply stores and it is safe to handle. Another option would be to smash highlighters and squeeze the liquid from the center into a bowl. You would probably need a lot of highlighters.

If you are using (and you probably should be) the chemical florescein a little goes a long way but you want to start out with a small container of water and add enough that the liquid turns a deep, almost amber, yellow. You will then water it down from this concentration.

Step 6: Soaking in Small Containers at First

You want to have them absorb as much of the coloring as possible at first so dump your dry grow spheres into small shoe box sized containers with just the food coloring. Slowly add water as they absorb the color. You'll see little bumps form on the surface of the water when it's time to add water.

Step 7: Transfer to Larger Containers

Eventually the shoe box size container will not be large enough and you'll have to transfer your spheres. This happens surprisingly quickly considering all 9000 of those spheres absorb 800 times their mass in water.

Step 8: Strain Your Spheres

After about a day the spheres will reach their maximum size. At this point you want to strain and rinse them off with water. We used a giant pasta strainer to do this. If you neglect this step then the spheres will die your hands a little when you touch them.

Step 9: Start Filling Your Glassware

We had two different types of glassware loosely designed to look like giant drink glasses. By complete coincidence they both needed about 100 grow spheres to fill them.

Step 10: Add Lights

We picked up these led ice cubes to light up our displays. They have a bunch of different settings but blinking was the obvious choice.

Step 11: The Finished Product

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    The images are gorgeous, they make an awesome centerpiece. Glad that you chose shared your methodology with us!


    Reply 8 years ago on Introduction


    Seeing that you're an editor here at Instructables I assume I have you to thank for featuring my instructable on the Living page. Super excited considering this is my first entry!

    Striking centerpieces and definitely a conversation piece. Two questions though: do the colors bleed when you mix two colors in one glass? AND what did you do with them when the event was over? I am thinking they could still stain carpet or clothes with the food coloring in them.


    Reply 8 years ago on Introduction

    This is a great question that I forgot to address. I'll make some edits later to the guide.

    You want to add the spheres together the day of your event. If you try to get cute and save time by mixing them the day prior they will slowly bleed overnight. As you can see by some of my photos it looks like a few of the mixed pieces are bleeding together but that is mostly an effect of the light passing both through the blue and orange which makes a kind of amber brown light. When I've done this in years past making the orange spheres a lighter color prevents this from happening quite as much.

    Possibly choosing two colors that compliment each other more would help with this as well? I'll leave it for you to try!

    They really don't stain anything once they are fully grown. We have these centerpieces out to play with at our annual black tie fundraiser event and it has never been an issue staining clothes in the years that I have done this with this technique. Keep in mind these guys start out absorbing most of the food coloring then it's just more and more water after that; lots of water. It is important to rinse off the spheres thoroughly before putting them in the glasses as stated in the instructable.

    Thanks for the interest!