RichGROW Calcium Nitrate + K is a very low ammonia form of Calcium Nitrate, used to provide Calcium and Nitrogen in a water-soluble form. Commonly used in a feeding program in an ‘A’ and ‘B’ tank system in greenhouse vegetable production. The low ammonia version is used to prevent a low pH rooting environment in the substrate which typically occurs in the frequent and high volume fertigation period between April and Sept.