Kids science: how to grow lentils in cotton

Ready for a fun and easy science experiment at home for kids? This is a fab opportunity to learn about nature, seed germination and plants. You’ll start with a few dry lentils and will have a nice plant in a few days.

plantar lentejas con algodonLentils in a jar: materials

  • Dry lentils
  • Glass jar
  • Cotton balls
  • Water


How to grow lentils in cotton in 4 steps

  1. Separate bits of cotton and put them at the bottom of the glass vase.
  2. Put a little bit of water to make the cotton wet.
  3. Place a few lentils on top of the cotton, pressing so they are stuck into it.
  4. Leave the vase somewhere with natural light. The experiment is ready!

lentils in a jar step by step

As you can see from our photos, my toddler enjoyed putting tons of cotton and dozens of lentils. Never mind! It ended up equally well and it’s her own personal style.

Over the next few days, we watered the cotton daily. Enough to keep the cotton wet without flooding it. We were very excited when the lentils started grow – every day they got bigger! It was really quick and fun to see.

When the lentil plant was too big for the jar, we carefully removed the cotton around the roots and seeds and transferred them to a pot with soil.

parts of plant lentils in a jarWhat we learned

This experiment was good to talk and learn about…

  • How does a seed become a plant? Germination and growing process
  • Why are light, temperature and water important?
  • Parts of a plant (see the image)
  • Why does the plant incline towards the light source and what happens if we move the jar around?


Experiment alternatives

You can also try this experiment with dry beans or chickpeas. If you’ve already done this science project or your kids are older, here are some other ideas:

  • Compare the growth and speed of lentils versus chickpeas.
  • Compare the growth of the seeds in light or in darkness.
  • Keep a nature journal. Write down the day of germination, first leaf…
  • Draw the progress each day to keep track of their growth.
  • Measure the length of the lentils as they evolve and keep track on a graph.


See more posts for babies and toddlers.

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