Experiment

Plant maze

How do plants find their way to the light?

Have you ever wondered why plants always grow toward the light? In this experiment, we will build a maze for a plant and observe how it finds its way to the light. In doing so, we will discover how important light is for different plants and how they react to it.

Did you know?

Did you know that some plants are so sensitive to light that they follow the sun throughout the day with their leaves? And when the light is too strong, plants detect the excess sugar in their leaves and produce their own “sunscreen” in the form of purple pigments called anthocyanins!

How does it work?

Plants need light for photosynthesis. This means that plants use light and other substances to produce, among other things, sugar, which they need to grow. Plants grow toward the light, a phenomenon known as phototropism. But what happens when the light is partially blocked?

To find out, we build a maze in our experiment. The direct path to the light is blocked, so the plant has to find its way.

You need:

  • A sprouting potato, spring bulb, or bean soaked in water

  • A small flower pot with potting soil

  • A shoe box with a lid and additional cardboard

  • Scissors

  • Glue or tape

  • Some water

Step 1

Place the sprouting potato, bean, or spring bulb in the flower pot filled with potting soil. Moisten the soil with a little water.

Step 2

Cut a large hole in one side of the shoe box to serve as the only source of light.

Step 3

Create two offset partitions with small openings (approx. 5 cm x 5 cm) from the cardboard and secure them to the box with tape so that the plant has a winding path to the light.

Step 4

Place the flower pot with the plant on the bottom of the box, opposite the hole. Then put the lid on the box and place it in a bright spot.

Step 5

Check the plant daily and water it when the soil feels dry. Take note of how it finds its way through the maze to the light.

Time to explore

Try repeating the experiment with different maze paths or different plant species. Observe whether and how the growth of the plants differs. Record your observations so you can compare the results.

Do different plants react differently to light?

Background knowledge

At the Institute of Science and Technology Austria (ISTA), scientists are researching the mechanisms of plant growth and cell communication. Eva Benková's research group is investigating how plant hormones such as auxin control the growth and orientation of plants. Such studies help us understand how plants perceive and respond to their environment, similar to our experiment with the plant maze.