What happens if I add eggshells (calcium)? We are doing a science experiment on plant growth in a cup. We are using calcium with brown and white eggshells, and one of our cups has no calcium in it. Which one will grow the fastest?
Adding Eggshells (Calcium)
Certified GKH Gardening Expert
It is difficult to say which will grow the fastest...that's the point of experimenting. While crushed eggshells are great for the soil, however, it usually takes some time for them to break down. Therefore, you may not see results right away as you might with other calcium mediums.
These articles have additional information that may help with your project: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-and-calcium.htm