Plant Nutrients
Plant Nutrition and Greenhouse Crop Fertilization
Fertigation Mixture Control - Fertigation injection control manifest for supplying the irrigation water line with the correct proportions of essential elements required for optimal plant growth.
Constant Fertilization during Irrigation
Often greenhouse growers follow a liquid feed program whereby water-soluble fertilizers are injected at precise dilution ratios into every irrigation. Whereas some growers elect to vary the fertilizer proportions at different stages of crop growth, many maintain the same injection ratios. Sufficient quantities of water must be irrigated to ensure thorough soil penetration; and, that soluble salts do not accumulate over time. Some growers supplement their liquid fertilizer applications with: controlled release fertilizers or slow release fertilizers; dry fertilizer applications; and micro elements or trace elements. Micro or trace elements, such as calcium and magnesium, are frequently incorporated into the substrate mix.
Fertilizer Injectors and Irrigation Water Lines
Most growers use fertilizer injectors to add macro elements to their irrigation water lines in order to assure the proper concentration of plant nutrients. Fertilizer injectors inject a small portion of stock solution into the irrigation water to create a dilute solution according to an appropriate fertilizer injector ratio for the greenhouse crop. In some fertilizer injectors the fertilizer injector ratio is set aka fixed and in others it is variable aka adjustable. High levels of fertilizer can cause toxicity or plant burn and low levels can lead to deficiencies. It is recommended to test the precision of the fertilizer injector, your set-up and the fertilizer itself. A portable electrical conductivity meter (EC meter) can be used to check the fertilizer solution and compare with the chart supplied by the fertilizer manufacturer on the fertilizer bag.
Organic Greenhouse Operations
Organic fertilizers made of decomposed or compostable natural materials are of high interest to farmers with such material available to recycle or to those serving the growing organic consumer market. Organic fertilizers, as solid or liquid form, can boost microbial populations and biodiversity, increase the amounts of micronutrients and trace elements, and improve the physical structure and characteristics of the growing media. There is a wide variety of suitable liquid and solid material: fish remains, composted farm plant matter and farm animal manures, seaweeds, waste mushroom substrate, etc. Because of the high variation, organic greenhouse farmers will need to do a lot of experimentation to realize sufficient productivity. Ideally, highly composted material is used as an additive to the substrate or in liquid form. Material that hasn't composted sufficiently will be more apt to harbor plant diseases and remove Nitrogen from the substrate.