All fertilizers, organic and synthetic, contain the three primary nutrients nitrogen, phosphorus and potassium. Fertilizers also contain a variety of secondary nutrients, such as calcium, magnesium and sulfur. According to the University of Missouri, sulfur is required for plants to synthesis amino acids, an important component of protein. Sulfur in starter fertilizer helps plants absorb protein nitrogen, which contributes to the quality of the vegetables or fruit produced by the plant.
Healthy Crops
Sulfur is an important secondary nutrient that influences the color and nutrients found in fruit and vegetable producing crops. According to the University of Missouri, sulfur deficient plants are common in gardens, which results in uniform yellowing of the plant and stunted growth. The symptoms of sulfur deficiency are similar to that of nitrogen deficiency. However, a soil test done by a University-based or private lab can help determine the nutrient levels in soil. Sulfur deficient soils benefit from starter fertilizer with a sulfur additive for healthy plant growth and development.
Lowers pH
pH stands for potential of hydrogen, which refers to the acidity or alkalinity of various soil types. The pH scale ranges from zero to 14, where zero is considered highly acidic, 14 is considered a base and 7.0 is considered neutral. Different plants require different pH levels, where a pH level of 8.0 may be suitable for one plant, may not be for another. According to the University of Guelph, sulfur in the form of aluminum sulfate and ammonium sulfate lowers the pH level in soils. The benefit of having sulfur in starter fertilizer is apparent for soils that are alkaline. Not all soils require lowering of the pH level, therefore a home test kit, found at most home and garden stores, is a convenient method for measuring pH levels without the help of a private lab. Sulfur additives in starter fertilizer vary between brands, therefore, the amount added may not have a substantial effect of pH level.
Nutrient Deprived Soil
Sulfur, naturally found in most fertile soils, is a necessary plant nutrient for growth and development. According to the University of Guelph, sulfur is a common pollutant near areas of industrial growth, thus supplying adequate supply to soils and plants. However, areas located west of heavy industry have soils that lack the necessary sulfur levels for healthy plant growth. Sulfur in starter fertilizer is required for plant growth where soils lack sufficient sulfur levels. Different varieties of plants require varying levels of sulfur, although typically low levels, therefore it is important to do a soil test before adding starter fertilizer with sulfur as an additive.
http://extension.missouri.edu/henry/Ag/Newspaper/2009/Roles%20of%20Calcium.pdf
http://www.plant.uoguelph.ca/performance_recommendations/ofcc/pub/sulfur.htm
http://gardening.wsu.edu/column/11-15-98.htm
