How Can You Test Your Soil?
Grade Level: 5-9
Source: Soil Science Society of America,
We walk around on soil all the time, but how often do we think about
what's in it? If you have ever looked closely at soil, you probably saw
that it is made up of various types of particles and has various materials
mixed in with those particles (rocks, twigs, water, air, worms, insects,
and much more). Those things you can see.
But did you know that soil also contains things that we can't see and
can only measure with chemical tests? These things -- acids, bases, nitrates,
phosphates, and potassium -- are chemicals that affect what types of plants
will grow well in the soil. As a citizen scientist, you can use a soil
test kit to find out how much of each type of chemical is in your soil.
- Soil test kit
- Local soil samples in plastic baggies
- Notebook to record results
- Water supply
- Paper towels
- Plastic gloves
- Get samples of soil from various places in your yard or around your
school (with your parents', guardians' or teacher's permission). You
don't need much -- about half of a small zip-closing plastic baggie
of each type will do. When you collect your samples, record in your
notebook where you found the soil and what kinds of plants, if any,
were growing in it.
- Put on the plastic gloves. Follow the directions on the soil test
kit to test your soil samples. Most kits from garden centers will measure
your soil's pH (how acidic or basic your soil is), as well as nitrate,
phosphate, and potassium content. Be sure to wash your hands and clean
up when you finish.
- Record the results of the tests in your notebook. Did all the soil
samples have the same results for each test? If not, how could you explain
that? Ask the people responsible for caring for the places where you
got your soil if they are adding anything to the soil. How could what
they were adding affect the soil?
- If your soil test kit has a list of plants that grow best in various
soil types, compare this to the types of plants you found growing in
your soil. Are these plants likely to do well in this soil? If not,
how can you change the soil so that the plants would do well? What would
you need to add to it?