This is a very good science project, but you should consider using at least five (5) pots of each soil.
You can take ordinary garden soil and bake it in an oven at 200 degrees F for an hour over three separate days. This treatment will kill any living organisms in the soil.
Plant growth promoting bacteria are generally in the Pseudomonas group. You will need specific growing media, sterilizing equipment and transfer tools to work with bacteria. I suggest you contact your local county agricultural office (if you have one) and talk with local microbiologists.
Science Experiments on Environmental Education and BiologyThe composition of the soil has important consequences on its ...
http://www.science-projects.com/safemicrobes.htm Micro-Organisms for Education ...
http://www.funsci.com/fun3_en/exper1/exper1.htm - 114k - Cached - Similar pages
Science Project Ideas, information and support for Science Fair ...Science Fair Project information and support for students, teachers and schools. ... The effectiveness of Antiseptics and soaps on household bacteria ...
http://www.scienceproject.com/ - 85k - Cached - Similar pages
Intermediate ProjectsProject guide and information for projects that are not bold font in our list, ... Field Studies -types of bacteria found in soil of different types [Exp] ...
http://www.scienceproject.com/projects/ ... termed.asp - 47k - Cached - Similar pages
Science Projects: Environmental Education & Outdoor Monitoring ...Soil acidification can also inhibit helpful soil bacteria. ... pH Module Test Kit; code #5890; Science Project Kit, pH; code #3-5873; Wide Range pH Test Kit ...
http://www.lamotte.com/pages/edu/project.html - 27k - Cached - Similar pages
Try these sites for more ideas.
Matt Mulanax