How to Grow a Bean Plant in a Cup with Your Kids

Learn how to grow bean plants in clear cups with your children for a fun, educational science experiment that shows roots and growth.

  1. Gather Your Materials. You'll need: dried lima beans or kidney beans (avoid split peas—they won't sprout), clear plastic cups, paper towels, water, and a warm spot with indirect sunlight. Optional materials include a spray bottle for misting and a ruler for measuring growth. Choose larger beans like lima beans since they're easier for little hands to handle and their growth is more dramatic to observe.
  2. Set Up Your Bean Cup. Take a paper towel and fold it to fit around the inside of your clear cup—this creates a sleeve between the cup wall and the center. The paper towel should touch the bottom and come up most of the way to the rim. Place your bean between the paper towel and the cup wall, about halfway down, so you can see it clearly from the outside. Add water to the bottom of the cup—just enough to keep the paper towel damp but not swimming. The bean should stay moist but not underwater.
  3. Create the Right Growing Conditions. Place your cup in a warm spot with bright, indirect light—a windowsill that doesn't get harsh direct sun works perfectly. The ideal temperature is room temperature, around 65-75°F. Check daily to make sure the paper towel stays damp by adding small amounts of water to the bottom of the cup. If the paper towel looks dry, add just enough water to make it moist again.
  4. Watch and Record the Growth. Within 3-5 days, you should see the bean start to crack and a small root (called a radicle) begin to emerge. This root will grow downward first. A few days later, you'll see a stem start to grow upward. Keep a daily log with your child—measure the root and stem growth, draw pictures, or take photos. The first leaves (cotyledons) will appear as the stem grows taller, followed by true leaves.
  5. Troubleshoot Common Issues. If nothing happens after a week, your bean might be too old or damaged—try fresh beans. If you see mold, you're probably keeping things too wet—reduce water and ensure good air circulation. If growth stops or the plant looks droopy, check that you're maintaining consistent moisture and that your plant isn't in direct, harsh sunlight. Some beans simply won't germinate, and that's normal—it's a great lesson about how nature works.