Growing kitchen scraps brings hydroponics to the classroom. You can do it for simple exploration. Alternatively, use vegetable parts to teach kids about scientific experimentation. By manipulating one little variable, they can learn a lot. Sure, they’ll better understand hydroponics. Additionally, however, they’ll conduct a fair test.

Growing Kitchen Scraps in the Classroom
Growing kitchen scraps engages kids in hydroponics. In my long career as a fourth grade teacher, I often brought stuff from home to grow. For a short life science activity, we just stuck a food parts in water. For example, the bottom end of a bunch of celery, the top end of a carrot, any part of a potato grow well. No need for much instruction. Kids learn by observing over time.
Kitchen Scraps and the Fair Test
With that said, however, these activities can be so much more! To integrate scientific practices, conduct a fair test. In other words, let kids compare what happens when one variable is manipulated. Grab this freebie to guide your students. They’ll learn the importance of controls. Additionally, you’ll teach them terms like independent, controlled, and dependent variables.

Let’s explore a few possible comparisons.
Do Kitchen Scraps Grow Better When Suspended or Immersed?
When I googled “growing kitchen scraps,” lots of images appeared. Some were suspended with toothpicks, like the image below. However, some also set directly in the water. Which is better?
To try this fair test, you can use the top end of a carrot (or another vegetable known to grow through hydroponics), as shown. Your students need two set-ups. First, they will place a carrot part directly into the water. Second, they suspend another carrot part. This way, they can determine which works better.
However, with this comparison, kids need to be especially aware of their controlled variables. For example, the amount of water, type and circumference of container, amount of carrot immersed, size of carrot part, etc. should be the same.

Which Part Grows?
When I looked at images of celery parts, they all showed the bottom end of the bunch (as shown below). But would another part of the celery also grow?
Additionally, I saw onions and potatoes sliced different ways. That made me wonder. When growing kitchen scraps, does the part I pick matter?
For this lab, students first choose a type of kitchen scrap. Then they prepare two separate set-ups with different parts of the scrap.

Right-Side Up or Upside Down?
Does position matter? Kids can also ask which way a kitchen scrap should be positioned. For example, I tried two pieces of the same potato. In the first set-up, I put the cut side down. Then, for the second, I put the skin side down.
Surprisingly, roots began growing out of the skin side that was placed in the water. Furthermore, stems began to grow out of the eyes of the potato. Kids can learn a lot with this simple experiment.

If you’d like, your entire class can participate in a simple challenge. One year, I gave each group of students one-fourth of a sweet potato. “Let’s see who can grow the biggest sweet potato plant,” I said. Much to my surprise, we soon had sweet potato plants – with really long vines – growing all along our window sill.
Learning from Failure Points
Of course, sometimes you fail. When growing kitchen scraps – or anything – things can go wrong. Not all plants make it. For example, a fungus grew on this sweet potato. Therefore, the experiment was a dud. Or was it? Failure in scientific experimentation teaches an important lesson: try, try again.

Enjoy Teaching
Growing kitchen scraps made me enjoy teaching even more. Bringing active learning into life science makes it more fun for everyone.
Try some plant science today! You can germinate seeds in a baggie, conduct a hydroponics STEM challenge, or just grow some scraps from the kitchen.



