From Scraps to Sprouts: Growing Plants from Kitchen Scraps

Every year, the United States wastes between 30 and 40 percent of its food supply. There are many factors, from crop loss in the fields to spoilage at the grocery store. And at the end of the supply chain, in communities where curbside composting isn’t offered or where backyard composting isn’t feasible, uneaten food goes to landfills.¹ (Want to try composting at home? Check out this worm bin project.) From landfills, decaying food releases methane, a powerful greenhouse gas, into the atmosphere, contributing to climate change. (For hands-on experience, try this greenhouse effect experiment with your kids.)

Did you know? Methane contributes 10 percent of all greenhouse gases, and nearly 60 percent of that is estimated to come from decaying food waste in landfills.²

Composting plays an important role, but we can also make an impact by reducing the amount of food we buy and making good use of kitchen scraps. Recipes that use vegetable trimmings (making your own vegetable stock from odds and ends, for example) provide a tried-and-true way of reducing food waste. You can also stretch some of those scraps by allowing them to propagate in water with this kitchen scrap gardening experiment that teaches kids more about how plants grow and how to make do with less while providing an opportunity to learn about environmental and biological science.

Growing a Kitchen Scrap Garden

What You’ll Need

• Bowls or jars, one for each scrap
• Windowsill, ideally with south-facing light, or a grow lamp (warmer places are ideal)
• Sharp knife (for adult use or for older kids with adult supervision)
• Kitchen scraps
  • Green onion/scallion bulbs (white parts with roots)
  • Celery bunch bottoms, at least 2 inches
  • Lettuce hearts (green leaf and romaine work well)
  • Paper and pencil for recording findings

How to Do It

1. Pour water in your bowls or jars.
2. Clean the knife blade with soap and water. Carefully slice a thin layer off the top of the scrap to ensure it’s clean. This will help keep mold from forming during the experiment. 
3. Place food scraps, cut side up, in the water. 
4. Set the containers under a grow light or on the windowsill.
5. Measure the scraps. Ask kids to record their observations in a journal. How do the scraps look on day 1? 
6. Drain and replace the water every day or two. Monitor your scraps carefully for mold, and compost or dispose of any plants that develop it.
7. Every few days, ask kids to observe and record their findings in a garden journal. Have the scraps grown? Note any changes in appearance and measure their length. Have roots formed?
8. After a week, green onions should be ready to harvest. After 10 to 12 days, lettuce and celery should be visibly taller. Harvest the leaves or stalks. How do they taste?

Why It Works

Kids may be familiar with how plants grow from seeds, but this experiment uses the properties of vegetative reproduction (a type of asexual reproduction) that some plants possess to propagate a new plant from an existing one. Green onion stalks (and other alliums), and the hearts of celery and lettuce are plants that contain everything the plant needs inside their stem. These plants can be cloned from existing parts to grow a new plant that is identical to its original. 

Ideas for Discussion

1. Ask kids what they think plants need to grow. Will the plants get everything they need?
2. At the end of the experiment, ask them to review the changes in their garden journal from day 1 to harvest. Which plants grew the fastest? What changes did they notice (celery leaves from stalks, green stalks from white onion bulbs, etc.)? Why do they think that is? 
3. Repeat the experiment with a new scrap and one that’s been used before. After several days, how are they similar? How are they different? When it’s time to harvest, try a taste test. Is there a difference in flavor or texture between the two? If they are different, what might be the reason?
4. Ask, “How do you think food scraps can help save resources? What effect could growing food from scraps have on the planet?”

For even more STEM-based learning opportunities, sign your child up for one of STEMful’s programs to help sprout their curiosity and set them up for success in the classroom and beyond.

1. “Food Waste FAQs,” USDA, accessed April 15, 2025, https://www.usda.gov/about-food/food-safety/food-loss-and-waste/food-waste-faqs.

2. “Quantifying Methane Emissions from Landfilled Food Waste,” EPA, last updated March 20, 2025, https://www.epa.gov/land-research/quantifying-methane-emissions-landfilled-food-waste.