This indicates the nitrogen level is low. On the other hand, manufactured nitrogen fertilizers are normally made from petroleum or natural gas. Typical release rates vary from a few days to a few weeks, giving a quick response after fertilizer application. They also may require some processing by soil bacteria. The phosphate and potash in manufactured fertilizers generally are processed from rock deposits.
Costs are comparatively low to moderate.
Because manufactured fertilizers are relatively high in nutrient content, only small amounts are required. On sandy soils, an overapplication of nitrogen can leach into groundwater. Both types of fertilizer will pollute our groundwater, lakes and streams when spilled or spread onto streets, sidewalks and driveways. Neither will pollute when correctly applied to lawns and Garden soils. Permission is hereby given to duplicate this Plant talk Colorado TM script as is if credit is given to the sources.