Bean in a Jar Experiment for Kids

The bean in a jar experiment for kids is one of the easiest science activities you can do at home. All you need is a jar, a paper towel, and a few dried beans. Your first block of text...

Because the beans grow against the glass, children can watch what usually happens underground.

The seed swells, a root pushes down, and a green shoot reaches up toward the light. Your second block of text...

Bean in a jar experiment for kids: bean seeds sprouting roots and a green shoot against a wet paper towel in a glass jar on a sunny windowsill

It works any time of year, so it's a perfect indoor fall or winter project for homeschool, the classroom, or a rainy afternoon at the kitchen table.

Most beans sprout in just a few days, so even young children stay excited from start to finish.

Two children watching bean seeds sprout roots in a glass jar on a kitchen windowsill

What You Will Need for the Bean in a Jar Experiment

What you will need for the bean in a jar experiment: a clear glass jar, paper towels, dried bean seeds, water, a ruler, and a bean journal with crayons

A clear glass jar. A pint canning jar or an empty pickle jar works well. A clear plastic cup is safer for little ones.
Paper towels. Two or three sheets, folded to fit inside the jar.
Dried bean seeds. Large lima beans are the easiest to watch. Pinto beans and bean seeds from a garden seed packet work too. Dried beans from the grocery store usually sprout fine.
Water. Enough to keep the paper towel damp.
A ruler. For measuring how tall the sprout grows.
My Bean Journal and crayons. Our free printable, below, for drawing what you see.

How to Do the Bean in a Jar Experiment

Soak the beans overnight. Put 4 or 5 beans in a bowl of water before bedtime. Soaking softens the seed coat so they sprout faster.
Line the jar. Fold the paper towels and press them around the inside of the jar, against the glass.
Wet the paper towel. Pour in a little water so the towel is damp all over, then pour off the extra. It should be wet, but the beans should not sit in a puddle.
Tuck in the beans. Slide 3 or 4 beans between the paper towel and the glass, about halfway down, spaced apart so each one is easy to see.
Find a warm spot. Set the jar on a windowsill or counter that is warm but not in hot, direct sun.
Check every day. Add a few drops of water whenever the towel starts to dry out. Draw what you see in your bean journal.

What to Watch For, Day by Day

Day 1 to 2: The beans swell up as they drink in water, and the seed coat may wrinkle or split.
Day 3 to 4: A small white root pokes out and grows downward.
Day 5 to 7: Tiny side roots branch out, and a curved shoot starts growing up toward the light.
Day 7 to 10: The shoot straightens, and the first green leaves open. Measure it with your ruler!

Every bean grows at its own speed, so don't worry if yours are a day or two ahead or behind.

Free Printable: My Bean Journal

Kids draw their bean on Day 1, 3, 5, 7, and 10, write a few words about what changed, and measure how tall it grew. It's made for grades K-2.

Click here to print My Bean Journal (free PDF)

Try These Bean Experiments Next

Light or dark? Start two jars and put one in a dark cupboard. Do both beans sprout? Which one stays green?
Turn it upside down. Once the root is about an inch long, gently turn the jar on its side. In a day or two, the root bends to grow down again.
Plant it outside. When the first leaves open, move your sprout into a pot of soil and watch it grow into a real bean plant.

Bean in a Jar Questions

How long does it take a bean to sprout in a jar?

Most beans grow a root in 3 to 4 days and green leaves in about 7 to 10 days. Soaking the beans overnight first and keeping the jar warm helps them sprout faster.

Why didn't my beans sprout?

The paper towel may have dried out, the spot may be too cold, or the beans may be too old. Try fresh beans, keep the towel damp, and move the jar somewhere warmer.

What if my beans get moldy?

A little fuzz means the jar is too wet. Throw out moldy beans, use a fresh paper towel, and add less water next time.

Can kids eat the beans?

No. Raw dried beans are not safe to eat, so remind children these beans are for growing, not snacking. Grown-ups should help younger children, since beans are small enough to be a choking hazard.