Many urban soils are disturbed during the construction process. Top soil is often scraped off and removed and, as a result, nutrient and organic matter levels are lower in these disturbed sites than in native soils. One of the factors necessary for optimum plant growth is the proper supply of plant nutrients. There are 16 essential elements required for plant growth. Thirteen of these are derived from the soil. When soil nutrient levels and/or soil pH levels are out of balance, supplemental nutrient applications or pH adjustment become necessary. Adding organic matter as well as nutrients may be necessary to improve the growth of plants on these sites. Accurate nutritional recommendations are important, because problems can result from either nutrient deficiency or toxicity. Soil testing and site analysis help us to pinpoint the problem.