Bean in a jar

This investigation is very simple but fascinating. Did you know you can grow a bean in a jar with just a little water?

How to grow a bean in a jar

What you need

  • A broad bean seed
  • Jar
  • Kitchen roll or a napkin
  • Water


  • Swirl a small amount of water around the jar.
  • Fold your napkin or kitchen roll and place in the jar. ( we made the kitchen roll very slightly damp also )
  • Place the bean seed in the jar resting on the napkin.
  • Spray some water on the bean every few days.

The bean should start to grow roots after a few days, this is called germination.

bean in a jar

We kept one bean in the dark and one in the light, both germinated and grew into small bean plants. This shows that light is not necessary for germination.

You can see here that the plant grown in the dark is a slightly less green than the one grown in the light. We have seen this before with the cress.

bean in a jar


Bean in a Jar grown in the dark

What amazes me the most is that all this can grow from one tiny seed with no additional nutrients other than those contained in the bean itself.

After a few days in the light the bean plant kept in the dark was as luscious a green colour as its counterpart.

Bean in a jar

Extension task

Try dissecting  a plant or try one of our other fun plant science activities.

Suitable for:

Key Stage 1 Science


Identify and describe the basic structure of a variety of common flowering plants, including trees.

Bean in a jar

There are 22 comments

  1. Bobbi Capwell

    I love this idea. It is so much better than the ziploc bag on the window. (Maybe it is just me, but those always get so nasty.
    Plus it would be great to have where the students could see actually grow and record the height.
    Love it.

  2. Carrie

    How fun!! I love the lessons where they get to see the roots that would be underground. Thank you for sharing at Sharing Saturday! I hope you are having a great week!

  3. Amber

    We grew a bean in a glass Mason jar for each kid a couple months ago. Can you believe they ate still thriving? One even grew a bean pod with beans in it. I should transfer them to a pot with soil.

  4. Maria

    I would like to know just why this works. Why is the one kept in the dark white? I know it has something to do with light. And why did it grow faster that the one in the light? Thank you!

  5. Spring Growth Project

    […] waiting for a tomato to sprout and grow, you can still show kids this magic.  Emma Vanstone has a helpful tutorial on Science Sparks for watching a bean plant sprout inside, where children can study the whole plant roots and all. […]

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