What is soil made of?

Plants grow from seeds.  They need soil, water, sunlight, and room to grow.  Today we made our own soil, so that we can find out what kind of soil grows the healthiest plants.

Question:  What kind of soil grows the healthiest plants?

Hypotheses:  Zoe and Zane both think that Soil 2 will grow the healthiest plants.  They predict that Soil 3 will grow the least healthy plants.

Materials:

Three plastic bins
clay (we got some from the backyard)
silt (we visited a local river to collect silt from the banks)
sand
organic material or humus (dead leaves, grass, plants)

Soil 1

Components	How Much?
Clay	1 cup
Humus	1/2 cup
Silt	1/2 cup
Sand	1/4 cup

Soil 2

Components	How Much?
Clay	1/2 cup
Humus	1 cup
Silt	1 cup
Sand	1/2 cup

Soil 3

Components	How Much?
Clay	2 cups
Humus	1/2 cup
Silt	1 cup
Sand	1 cup

Pictures of our soil:

Results:

We planted 4 beans in Soil 1, 4 more beans in Soil 2, and 4 more beans in Soil 3.  Check out our post about planting the beans to find out which soil type grew the healthiest beans.