Growing Plants in Test Tubes

Sick Science! Summer Camp - The science of seeds and water conservation.

There’s nothing better than fresh fruits and vegetables picked right out of the garden in the summer. But what’s happening in that garden while the food is growing? Here are two experiments to do in the garden to learn the science behind plants and water conservation. 


The best way to save on water in your garden and keep your plants nice and happy is to use Water Jelly Crystals in the soil around the roots.

Experiment Materials

  • Water Jelly Crystals
  • Baby Soda Bottles and Rack OR clear plastic cups
  • Dirt
  • Pipette or something to drop water into the test tubes
  • Seeds


The Diggin’ Dirty Science Kit will have complete instructions to step you through. Or, if you choose to do this without the kit, you can use clear plastic cups or Baby Soda Bottles.

  1. Hydrate the water jelly crystals. It will take about an hour or less to get the crystals fully hydrated. If you are a regular reader of our website, you know water jelly crystals are polymers and come as a small, hard pebble. Soak them in a bowl of water and the crystal will absorb water and grow. The hard pebble becomes a soft, jelly-like crystal.
  2. Soak the seeds in water for an hour or more to soften.
  3. Thoroughly soak the dirt but don’t flood it.
  4. Fill each Baby Soda Bottle or plastic cup about 1/2 full with dirt. The dirt should have food or fertilizer for the seeds.
  5. Fill one Baby Soda Bottle with Water Jelly Crystals 1/2 full. 
  6. Add a seed or two into each container.
  7. Fill to 3/4 full with dirt or Water Jelly Crystals to cover the seeds.
  8. Place in a sunny location.
  9. Water every 2 days or so with a few drops of water from the Pipette. Don’t oversaturate the dirt, especially since the Baby Soda Bottles do not have drainage holes.
  10. It will take 4 to 7 days before roots start to emerge and then the seedlings begin to grow.
  11. Look at and study the roots and seedlings. You will be able to see exactly how they form and grow out of the seed.
  12. Transfer to a sunny, outdoor location after two to three weeks.

How Does It Work?

This experiment demonstrates how seeds grow and sprout in the soil or Water Jelly Crystal environment. After you grow plants the first time, try it again and test different types of dirt or materials in the test tubes. Or experiment with amounts of water. What happens to seeds in a drought?


The roots begin to grow and establish several days before the plant begins to grow. With the clear container, you will be able to see something happening well before you would in a traditional pot. You will also observe how the plant stem and leaves grow out of the seed and begin to make their way to the surface. Keep a log and make notes and drawings everyday to track your plants’ progress. Also compare the seeds in the dirt vs. the seed in the Water Jelly Crystals. Does either one grow faster or better? Farmers and gardeners are using Water Jelly Crystals to help conserve water. They are available through Steve Spangler Science or at local garden stores. Hydrate the crystals. Dig a hole for your plant, add a handful of Jelly Crystals at the bottom of the hole, add the plant and cover with dirt. The crystals will provide water for the plant as they dehydrate. The plant won’t need as much watering, especially during heat waves.

Allow about 45 minutes on the first day of set up to allow for soaking of the dirt, seeds and Water Jelly Crystals and get the seeds planted. You will need less than five minutes every other day or so for the next two weeks to water and observe your seedlings.