Chapter 19

Fertilizers for Greenhouse Crops

(book excerpts)

Maintaining adequate nutrition is among the most critical aspects of producing greenhouse crops. Fertilizers are primarily valued for their ability to supply nutrients. They typical fertilizer provides proportions of the three major plant nutrients; nitrogen, phosphorus, and potassium. The secondary plant nutrients such as calcium, sulfur, and magnesium are also contained in fertilizers. Fertilizers also contain micronutrients such as boron, manganese, iron, zinc, copper, and molybdenum. Fertilizers can be placed into categories of inorganic fertilizers and organic fertilizers. Inorganic fertilizers are materials that are mined or synthesized from non-living materials while organic fertilizers are materials that are derived from plants and animals. While it is difficult to make direct comparisons between these two sources, inorganic fertilizers are the prefierred choice in most greenhouse operations for several reasons. First, inorganic sources are typically high analysis fertilizers, while organic sources are low analysis. This means that inorganic fertilizers contain a larger percentage of a given nutrient than organic sources. As a result, inorganic fertilizers are applied in lesser amounts than organic sources, since it takes less inorganic fertilizers to achieve a given rate. Secondly, composition of organic fertilizers is generally much more varied than inorganic fertilizers. This lack of consistency can make it difficult to predict how much organic fertilizers should be applied to obtain a desired rate. Finally, organic fertilizers are typically several times more expensive per nutrient compared to inorganic fertilizers.

Click on the following topics for more information on fertilizers for greenhouse crops.

Topics Within This Chapter:

  • Inorganic Fertilizers
  • Fertilizer Grade
  • Other Nutrients
  • Regulatory Standards
  • Fertilizer Formulations
  • Complete versus Incomplete Fertilizers
  • Fertilizer Forms
  • Solid Fertilizers
  • Liquid Fertilizers
  • Water-Soluble Fertilizers
  • Fertilizer Acidity/Basicity
  • Fertilizer Salt Index
  • Controlled- and Slow-Release Fertilizers
  • Advantages and Disadvantages
  • Controlled-Release Fertilizers
  • Slow-Release Fertilizers
  • Chelates
  • Organic Fertilizers
  • Fertilizers Labeled as �Organic�
  • Animal-Derived Fertilizers and Amendments
  • Plant-Derived Fertilizers and Amendments
  • Seaweed Fertilizers and Amendments
  • Mined Mineral Fertilizers
  • Methods of Fertilizer Application
  • Fertigation
  • Foliar Fertilization
  • Advantages and Disadvantages in Foliar Fertilization
  • Foliar Application Considerations