This experiment was designed to test the growth of plants when only receiving light from a certain direction. We had one 'Control' plant that only received light from above, and one 'Test' plant that only received light from beneath it.
Phototropism refers to how plants grow in response to light.
Gravitropism refers to plants ability to shoot their roots down and their leaves and stems up.
We wanted to test which had a stronger influence on the stems and leaves by only giving a plant light from below.
Step 1: Materials Needed
To make the same basic design for this project that we did, you will need:
- 2 large upright boxes.
- 2 50 watt LED lights with wall plugs.
- 1 milk crate.
- Hot glue gun and glue.
- Exacto knife
- Plexiglass or greenhouse wall material.
- 2 clear drip trays.
-2 plants of the same variety.
Step 2: Step One
Start by taping or gluing one end of each of the boxes. Then cut a circle into the closed end of the boxes for the lights to fit in to. Feed the light and cord into place and secure them using wood scraps and glue.
Place the milk crate under the box with the light underneath it so it can stand up properly. Feed the cord through the holes in the crate so you can plug it in.
Step 3: Step 2
Cut the plexiglass or greenhouse material to the dimensions of the boxes so that it fits in the box securely. On the box with light from below you can choose to put extra supports beneath the transparent material. The material should be around 4-6 inches from the light.
Step 4: Step 3
Cut a doorway on the sides of the boxes and then close the open end of the boxes.
After that you should be ready to plug in the lights and place your plants and drip trays in the boxes.
Step 5: Step 4
Now you should be ready to plug in the lights and place your plants and drip trays in the boxes.
Step 6: End Notes
You can then monitor the plants and how they differ in growth. You can also set up a time lapse camera and an automatic drip system to make it easier.
We observed that over the course of a month the control plant grew normally and the test plants leaves began to grow close to the main stem. The control plants leaves moved to be vertical and faced the sides of the box to catch the light coming up.
A recommendation is also to paint the inside of the boxes flat black to reduce reflection.
Also try to use quick growing young plants for more visible results.