Control Algae lives in wet areas such as lakes, ponds, and coastal regions. It does not cause disease, but it does stunt the growth of surrounding plants. It forms a slick green or black layer on soil surfaces as well as over low grasses and lawn areas. Once algae covers your plants, air and light cannot penetrate the coating as well therefore causing the damage mentioned above. Some causes of algae abundance are compacted soil, too much nitrogen, too much shade in moist areas, and lack of air circulation.
Low nitrogen is best.
Proper soil drainage. Add some sand if you have to loosen it up some. Proper light sources. Too much is a bad thing. Used under License.