Growing Kitchen Scraps in the Classroom – More Hydroponics

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.

Sweet potatoes grow in a bowl of water. It's a great way to teach kids about hydroponics.

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.

When growing kitchen scraps in the classroom, take your activity to the next level. When kids compare and control, they can conduct a fair test. Grab this free lab sheet to guide your students.

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.

Growing kitchen scraps gives kids an opportunity to experiment with hydroponics. Let them experiment with the part that will grow. For example, here we see that the end of a bunch of celery works. Will other parts?
Are you feeling “pinspired?” Feel free to pin images from this post.

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.

Growing kitchen scraps gives kids an opportunity to experiment with hydroponics. Let them experiment with the part that will grow. For example, here we see that the end of a bunch of celery works. Will other parts?

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.

When growing kitchen scraps in the classroom, embrace the fair test. Here, for example, you see what happens when different sides of a potato half are immersed in water. Roots grow out of the cut side, but stems grow from the eyes.

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.

When growing kitchen scraps, kids will encounter failure. For example, in this picture, some sort of fungus grew on the sweet potato. Therefore, roots and stems did not grow.

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.

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