Grow a Seed in a Bag & Plant Life Cycles: Simple Science for Kids

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Looking for a low-mess, high-impact science experiment that brings plant biology to life? Growing a seed in a bag is a simple, visual way to teach kids about seed germination and plant growth—right from a windowsill. Plus grab a pea plant life cycle to learn about the plants as they grow!

This classic botany activity is perfect for the classroom, homeschoolers, co-ops, or curious kids at home. All you need is a seed, a bag, and a sunny window. Often this is done with a bean seed, but we decided to try pea seeds in ours instead! 

What Kids Learn from Growing a Seed in a Bag:

• Plant life cycle and stages of germination

• Observation and journaling skills

• Basic needs of living things (light, water, air)

• How roots and shoots grow

This is a great precursor to planting a real garden or studying photosynthesis. You are making your own little greenhouse!

Supplies Needed:

• 1 Ziploc bag

• 1 or 2 dried seeds (peas or beans such as lima, pinto, or kidney work well)

• 1 damp paper towel or cotton ball

• Water

• Tape (to hang the bag)

• A sunny window

• Optional: Plant observation journal or worksheet

Instructions for the Seed in a Bag Experiment:

1. Soak Your Seeds

• Place a few seeds in a bowl of water to soak for at least 6 hours. 

2. Prep the Paper Towel

• Fold a paper towel into quarters and dampen it—moist but not dripping.

• Place the folded towel inside the sandwich bag, laying it flat.
  
  

3. Add the Seed

• Slide one or two dry seeds between the paper towel and the side of the clear plastic bag so that you can see them clearly.

4. Seal and Hang

• Seal the bag to keep the moisture in.

• Use tape to attach the bag to a sunny window—a south-facing window works best.

5. Watch It Grow

Over the next 3–7 days, kids will see the seed swell, sprout its first roots (the radicle), and send up a shoot (the plumule).

Keep an eye on moisture levels—if the paper towel dries out, spritz lightly with water. 

This is really a cool activity to watch the whole process of how a plant grows. 

Extension Activities:

• Draw and label the parts of the seed or plant as they appear: seed coat, root, shoot, leaves.

• Record daily growth observations in a plant journal.

• Try growing multiple seeds in separate bags to compare growth rates.

• Use different types of seeds to see if they sprout at the same rate.

• Print out the Pea Plant Life Cycle to accompany this! 

 

Download the Pea Plant Life Cycle Worksheets Now!

This two page printable comes with both a color and black & white version.  They are cut and paste worksheets to help kids learn the life cycle of a pea plant! 

 

Discussion Questions:

• What does the seed need to start growing?

• What happens first: the root or the shoot?

• How does the bean change over time?

• What might happen if we didn’t give it sunlight or water?

Take It Further:

• Transplant your plant sprout into a jar of soil once it has a strong root and shoot.

• Start a kitchen windowsill garden with herbs or veggies.

• Explore plant-based vocabulary: germination, photosynthesis, cotyledon, seedling.

Learning Tie-Ins:

• Science: Plant biology, ecology, scientific observation

• Writing: Journaling, labeling, drawing conclusions

• Math: Measure the sprout length over time

Growing a seed in a bag is a fantastic visual science project that requires little prep but yields big learning. It’s perfect for curious kids, budding botanists, or any family wanting to learn more about how plants grow.

See More Plant & Gardening Activities:

Kids Gardening Math: Growth & Measurement

How to Plant Seeds with Kids: A Fun & Educational Guide

The Seeds We Eat- Nature Science

Garden Ten Frame Printable Math Activity

Awesome Pumpkin Life Cycle Activities