What happens to a seed to make it sprout? Here’s an easy project that will help your child see how a young seedling comes to be. This project takes about a week, but you should check on it every day to see how a plant develops.
Every seed has a baby plant sleeping inside; all it needs to wake up is a little moisture. Once the moisture reaches the seed it will swell up and burst out of its seed coat. The roots will grow down and later the stem and leaves will grow up. The first leaves are called “cotyledons” or seed leaves. These seed leaves will look different from the plant’s true leaves. After the cotyledons start making food for the plant, the true leaves will develop and the plant will begin to grow.
What You Need:
• Large seeds, either beans or squash
• A clean glass jar with a wide mouth and lid. A clean peanut butter or jelly jar works well.
• Paper towels
• A garden journal and a camera (optional) to track the seed’s development
• Colored pencils for your child to draw what he/she sees
What To Do:
1. Roll the several sheets of paper towels into a tube that you can insert into the jar. Cut or fold the paper so it all fits in the jar.
2. Wedge four seeds between the paper towels and the side of the jar. Make sure the seeds are separated by at least two inches so new plants will not interfere with each other.
3. Add about an inch of water to the bottom of the jar. The water will wick up the paper and the seed will begin to germinate. Keep the paper towels moist by adding a little water when needed. The children can watch as the bean or squash produces a whole root system very quickly.
4. Check the seedling’s progress every day and have your child take a picture or draw and label what he/she sees.
5. Once you can see the first true leaves have your child plant the seedlings in the garden.
Here’s a modification of this project that addresses the question, “How do seeds know to grow their roots down?”
Gravitropism (also called geotropism) is the directional growth of an organism in response to gravity. Plant roots display positive gravitropism, which means they grow in the direction of gravity. Ask your child what do you think happens if there is no gravity? Other factors such as light and temperature will affect the seedling’s development.
The first three or four days will be the same as above, but once you see the root start growing, turn the whole jar upside down for two days and see what happens. Turn the jar again in two days to see the seedling reverse itself.