Plants can tolerate a wide range of watering and nutritional conditions. However…for a commercial operation, the bottom line is profit which means optimizing plant growth and yield. Optimum watering and mineral nutrition are critical for optimum plant growth. Optimum watering and nutritional conditions can vary:
- For different plant species
- For the same plant species at different times of its life cycle
- For the same plant species at different times of the year
- For the same plant species under different environmental conditions
Properties of the nutrient solution:
The physical systems required to deliver the nutrient solution to the plants. How to calculate how much of each compound to use.
DEFINITIONS
*Irrigation = The supplying of water to dry land using ditches, pipes, streams, etc.
*Fertilizer = Inorganic “salts” containing the essential macro and micro elements
necessary for plant growth. Also organic compounds that contain such elements (i.e., manure, fish emulsion, bat guano, etc.) that, when added to the soil or water, increase it’s “fertility”.
*Fertigation = The use of fertilizers (usually inorganic for commercial greenhouse hydroponics and smaller systems, though some hobbyists use organic mixtures), in the appropriate combination, concentration and pH, for every irrigation cycle.
*Nutrient solution recipe = A list of inorganic compounds, and their final concentrations in ppm (“parts per million” or “milligram per liter”) or mMol (millimole), etc. This can also include actual amounts of the compounds needed to achieve the prescribed concentrations, given specific tank volumes, dilution factors, etc.
NUTRIENT DELIVERY SYSTEMS
- Simple systems: Non-recirculating/air gap system or the raft system where the roots hang down directly into the nutrient solution. Basic wick system in which the nutrient solution is drawn up by an absorbent wick into an aggregate where the roots grow.
- Complex systems: The flood and drain, top feeder, NFT or Aeroponic systems all of which require pumps to move the nutrient solution from a reservoir or series of tanks to the plants via PVC, poly and drip tubing, emitters, etc.
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