Which soil is best for growing plants?
How do we know?
If your class is completing NGSS science experiments, then you’ll want science experiments that solve real-world problems.
Help kids complete the which soil is best for growing plants science project using these steps.
For this STEM activity, and seed germination experiment we wanted to know what kind of soil was best for sprouting seeds.
My kids created a seed sprouting science experiment to determine the best kind of soil. It’s the perfect addition to your spring STEM activities!
This post contains affiliate links for your convenience.
Which soil is best for growing plants science project
In this seed growth experiment, kids will learn which type of soil is best for growing plants.
Supplies for the seed jar experiment:
- Easy-to-grow seeds (we used corn seeds)
- 4-6 types of soil
- Small jars or pots (we used mason jars)
- Paper towels
- Plastic bag
How to Do the Seed Growing Experiment
Select a handful of seeds to pre-sprout between layers of damp paper towel inside a plastic bag. We placed our bag over the top of our refrigerator and they sprouted in about five days. This made the experiment yield faster results when we did it with the kids.
Fill your containers with the same amount of your soils. We filled our jars half-way with sand, flower potting soil, vegetable potting soil, dirt from the yard, and a mixture of half-sand/half-potting soil.
Plant three or four seeds in each container. We did three seeds per jar in case some refused to sprout. Use a pencil to push the seeds into the soil.
Water your seeds with the same amount of water per jar. We used about 1/2 a cup per jar.
Place your jars in a sunny location. Our seeds started to sprout leaves within on week. After two weeks, we compared soil types.
My kids thought that the vegetable potting soil would be best for the corn, which proved to be true. The surprise soil, however, was the sand. We thought that the sand would be worst for growing seeds, but our sand seeds were the second-most developed of the entire bunch.
Seed Germination Experiment Results
According to a planting guide we read after conducting our experiment, sandy soil is actually recommended for growing corn. We will keep a close eye on our sand plant to see how it changes and if the pure sand or sand/soil mixture will be best for the corn plant over time.
The worst soil for our corn seedlings was our yard soil, which is clay-heavy, not ideal for growing corn. Only one of the three corn sprouts we planted grew leaves.
Types of Soil Experiment STEM Extensions
We left our seeds in the individual soil jars to see if their growth will change over the lifetime of the plant. We wanted to know if growth changes over time depending on the current needs of the plant.
As seeds have nutrients already built-in, it is possible that soil that worked to sprout the seeds may not produce healthy plants over a period of months. We will keep checking progress until our plants grow too big for their jars or die.