Window Greenhouse

How do plants grow? In this experiment, you will create a mini greenhouse to learn how plants depend on sunlight and water. Place seeds in a Ziploc® brand sandwich bag with a wet paper towel and put the bag by a sunny window. Record your observations daily to see how long it takes for the seeds to sprout and grow leaves. What do you observe? Download our observation printable here.

  1. Ages: 5 - 11

  2. <30 minutes

  3. A little messy

  4. Grownup needed

Step-by-step tutorial

  • Step 1

    Gather your materials.

    Photo reference of how to complete step 1

  • Step 2

    Cover the seeds with water. Soak them overnight. (Soaking the seeds will help them sprout faster.)

    Photo reference of how to complete step 2

  • Step 3

    Fold the paper towel in half and cut it so that it fits in the Ziploc® brand sandwich bag.

    Photo reference of how to complete step 3

  • Step 4

    Dampen the towel. Gently wring it out so that it’s still damp but not dripping.

    Photo reference of how to complete step 4

  • Step 5

    Place the damp towel inside the bag.

    Photo reference of how to complete step 5

  • Step 6

    Place a few seeds on the paper towel inside the bag, an inch or two from the bottom.

    Photo reference of how to complete step 6

  • Step 7

    Lay the bag on a sheet of paper and sketch a house shape around it. Cut out the house shape, then cut out a window for the bag to peek through. Make sure the window is large enough to see all your seeds, with room to grow! If you want, draw on the greenhouse with markers or decorate it with paper cut-outs.

    Photo reference of how to complete step 7

  • Step 8

    Tape the bag and frame it to a window, with the seeds facing inside so that you can see them sprout. Keep track of how your seeds grow with our Observation Journal Printable! If you like, create more greenhouses and let them grow under different conditions or locations to observe what happens. Print additional journal pages to track their progress.

    Photo reference of how to complete step 8

  • Learn moreMagnifying graphic

    When the seeds have sun and water, they sprout. But do they need both sun and water? Make multiple window greenhouses and test it out! What happens if you place the seeds in a dark room with water? Or in a sunny spot without water? Or even in a dark place with no water? What do you see?

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