Germinate Seeds and Watch Them Sprout on the Windowsill

No need for dirt! In this gardening activity, your child will "plant" a bean in a plastic bag - then watch it sprout!

By Liz Heinecke
Feb 23, 2018



Germinate Seeds and Watch Them Sprout on the Windowsill

Feb 23, 2018

Get ready for gardening with this simple experiment that lets kids observe seed germination, minus the dirt!

Watching a sprout emerge from a dry seed is nothing short of miraculous. Plant a bean in a plastic bag to watch roots form and leaves emerge before your very eyes.

You’ll Need

  • Small plastic zipper storage bag
  • Dried, uncooked beans, peas, or seeds
  • Paper towels
  • Water 

Safety Tips and Hints

  • Dried beans are choking hazards for small children.
  • For this experiment, choose a window where the seeds will get plenty of light, but won’t be blasted by intense sun all day. If your windows are freezing cold, tape the bag to a clear glass or vase in a sunny spot indoors, rather than a window.

What to Do

Step 1: Have your child cut a paper towel in half and fold it a few times so it can fit into the zipper storage bag.

Step 2: Soak the paper towel in water and slide it into the bag. Smooth it so that it’s relatively flat.

Step 3: Let your child position two beans or seeds about three centimeters from the bottom of each bag, on one side of the paper towel. Don’t worry if they don’t stay in place, but if necessary, stuff a little piece of paper towel into the bottom of the bag so that the seeds aren’t sitting in water. 

Step 4: Seal the bag part way, leaving an opening near the top so the growing plants can get some air. 

Step 5: Tape the bag in a window with the beans facing indoors, so that your child can watch them as they grow. 

Step 6: Read the section below, on the science behind the fun, to your child so that she knows what to look for as the seed germinates and grows.

The Science Behind the Fun

Dried beans and peas are seed that contain dormant (sleeping) baby plants. These tiny plants need signals to make them “wake up” and emerge from the seed. Germination is the name for the processes the plant goes through in order to sprout from the seed and form leaves.

Plants need special signals to germinate, including light, air, and water. Temperature can also play a role, which is why you don’t want to put your seed against a freezing cold window.

When a plant first sprouts, it gets nutrients from the seed. You can see the seed shrinking as the plant grows. As a plant matures (gets older), it depends on roots and leaves to collect the energy it needs. Once it reaches a certain size and uses up the nutrients in the seed, your window sprout will have to be transplanted into soil to survive.

Creative Enrichment

Record the beans’ germination by drawing and measuring them each day. Have your child make a science notebook and use it to record his observations. 

What happens if you do the same experiment, but put one bag of beans in a window, and another one in a dark closet?

Plant more than one type of bean or seed to compare how quickly they grow.


You can find more experiments like this one at, and in my books Kitchen Science Lab for Kids (Quarry Books), Outdoor Science Lab for Kids (Quarry Books), and my upcoming book STEAM Lab for Kids: 52 Creative Projects Exploring Science, Technology, Art and Math (available wherever books are sold).

All photos © Kitchen Science Lab for Kids (Quarry Books)

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