Greenhouse & hydroponic
systems information
Magic or Simple Science ?
Practically all greenhouse crops today are grown with nutrient solutions.
I meet too many growers who think that proper greenhouse crop nutrition is by magic, and know of too many commercial interests who encourage this magic viewpoint regarding nutrient solutions. There are charlatans who sell growers high priced nutrient mixes made according to special secret recipes with no consideration of the particular nutrient requirements of the buyers crop or situation.
The true situation is that greenhouse crop nutrition is a matter of simple science, readily available to any grower who is prepared to learn. Growers who have the necessary knowledge can formulate and adjust their nutrient solutions using basic scientific principles to suit any crop situation and water supply and by doing so keep their fertiliser costs to a minimum, while optimising crop nutrition and performance in terms of yield and quality.
This part of GHVI attempts to provide the necessary simple science and information on the practical methods of formulating, adjusting and managing recirculating nutrient solutions for crops growing in liquid cultures (such as NFT, DFT and floating raft cultures) or in media (sawdust, pumice, coir, rockwool or whatever).
The information is on the following pages:
- Why bother ? reasons why growers should make nutrient solutions
- The essential chemistry and basic principles of plant nutrition.
- Conductivity and pH of nutrient solutions and practical considerations of measurement and control.
- Laboratory analysis of water and nutrient solutions, and understanding laboratory results.
- Variations in nutrient uptake between crops, with the development of individual crops, and between seasons and examples of solution specifications
- Calculating the amounts of fertilisers to use when writing a solution recipe to a specification.
- Fertiliser quality recommendations.
- Practical tips on how to make up nutrient stock solutions.
- Day to day solution management required in the greenhouse.
- Managing nutrient solution for optimum crop nutrient uptake.