Using Green Fertilizer for Hydroponics
The company I'm working for is now working hard to develop a design project of a highly-efficient heating system for a big greenhouse complex.
We now have an idea about using tomatos and cucumbers haulm for making biogas. The biomass is put into the tank, and then, a short time afterwards, we obtain biogas (which can be burned for getting heat energy and CO2) and some waste product which is used in soil agriculture as a good organo-mineral fertilizer. The only problem is that we don't know how to use this fertilizer in hydroponics.
I've read many articles in the Internet, and many of them say that organic fertilizers are not for traditional hydroponics. But the mass we want to use is almost completely steril, and we aren't going to use any other raw materials for biogas making. No stuff of animal origin, no garbage will be used, just the haulm of the plants. Can it be used or not in hydroponics or not? What do you think about it?
Answer from Stella/Simon:
I'm sorry Svetlana, but I do not think it could be used for a hydroponics system, here'e why...
In hydroponics, you take soil away from the plant, so you must supply perfectly balanced and complete nutrition for it.
Plants need large amounts of 6 macro-nutrients: Nitrogen (N), Phosphorus (P), and Potassium (K). The NPK numbers you see on a manure or fertilizer bag (like 30-10-30) are simply telling you at what ratio these three macro-nutrients are mixed in that bag of fertilizer. The other 3 macros are calcium, sulfur and magnesium. All 6 are provided in the proper ratio in all hydroponics solutions.
Plants also need micro-nutrients (minute traces of other elements) in order to thrive, just like you do. The nutrient solutions you buy for your hydroponics garden are different from ordinary plant fertilizers. They include all the trace elements, too. So hydroponic solution is kinda like your One-a-day Vitamins; it contains traces of iron, boron, manganese, zinc, molybdenum, copper, cobalt, chlorine, selenium and silicon.
The special hydro nutrients you buy supply everything in just the correct amounts.
Hope this helps!
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