In this edible indoor gardening science project, even very young scientists can enjoy the fruits (actually vegetables) of their labors! But unlike a typical backyard garden planted from seeds, this version allows kids to regrow vegetables from scraps in only a few days.

What You Need:

  • green onions (also try carrots, romaine lettuce, celery, onions, garlic, or potatoes)*
  • a beaker or small glass
  • water
  • knife and cutting board
  • an adult helper

*Note: The project instructions tell how to re-grow scallions, but it includes tips for growing other types of vegetables. Carrots will not grow new carrots, but they should grow new greens from the top. While carrot greens are edible, they tend to have a bitter taste. If you don’t care to eat them, they can be planted in potting soil once they have sprouted and be kept as house plants. The same is true for garlic. Sprouted potatoes and sweet potatoes are fun to watch grow, but require more steps to produce new potatoes.

What You Do:

  1. Have your adult helper cut the root end of each scallion (green onion) about 1” from the end. Save the root portions and use the remainders for cooking. For carrots, choose ones with at least a small about of green attached and save the top inch of the carrot. For romaine lettuce and celery, save the bottom 2” section of the heart.bottoms cut off green onions
  2. Place the cut scallion ends into the small jar and add just enough water to cover the roots. Empty, clean sour cream containers are a good size for the other types of vegetables; for each vegetable, cover only the lower third with onion roots in water bottoms cut off carrots
  3. Set the container(s) in a sunny spot, such as on a window sill.
  4. Pour out the water and refill to abouta half-inch every day. You should notice new green shoots in just a day or two and they should be long enough to harvest and use within 5 days. Carrot tops and celery hearts take a bit longer to grow, so be patient!regrowing green onions
  5. Romaine and carrot tops both grow quite well in soil. Once they have started to grow well, you can plant them in a pot of potting soil, or directly in the ground if you have a garden space! Cover the base of the vegetable with soil right up to where the new growth has started. Water them well, give them plenty of sun, and enjoy harvesting new vegetables from scraps of old ones! (See note* above about carrots.)new green onion shoots sprouting carrots

What Happened:

How is it possible for a vegetable to grow, even after it has been harvested? Plants are living things. They can continue to grow roots and sprout stems and leaves even after they have been removed from soil or from the main part of the plant they came from. But what do plants need to grow? They need water and sunlight to start growing roots and shoots. Plants can grow in water for a while, but will eventually need soil to get the proper nutrients to continue growing well.

Scallions are easy to grow in water because they already have roots that quickly soak up water to help the plant grow. Carrots are a root, and while putting a cut carrot top in water will not grow a whole new carrot, the green shoots will grow from the top of the vegetable after several days.

Have you ever noticed an onion or bulb of garlic with a little green shoot coming out of the top? Sometimes vegetables begin to sprout if they aren’t used up quickly enough. The same is true of potatoes and sweet potatoes!

Science Lesson

Have you ever planted a seed and waited for it to sprout something green above the soil? What happens below the soil? Roots grow down into the ground. In some plants, those roots grow larger and larger, becoming a vegetable that we can eat, such as a carrot or radish. Can you think of more examples of vegetables that grow as roots?

Some plants grow tall stems with small leaves and shallow roots. We eat the stems or stalks of one of these plants and sometimes use the leaves for seasoning or flavor in soups. Can you guess what vegetable this is? (Answer: Celery.)

What vegetables do you eat that are the leaves of the plants they grow on? Lettuce, spinach, Brussels sprouts, cabbage, and other greens are examples of leaf vegetables.

We even sometimes eat the flower and seeds parts of plants! Broccoli and cauliflower heads are actually the flower part of their plants while peas and corn are seeds.