Discussion in 'Plants: Science and Cultivation' started by Daniel Mosquin, Oct 6, 2003.

  1. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    Vancouver, British Columbia, Canada
    The following was received via email:


    I am a Vancouverite far from home, can you help me?

    I am doing a project here in the Philippines, In the Visayas. I am examining the feasibility of Hydroponics strictly on locally sourced resources.

    We are at Latitude 9 deg North, temperatures over 30 deg most of the time.

    I am running (approximately) Resch's A, B, C, mixes, dripped into the local coconut tree sawdust, mixed with rice-hull. I am recirculating the nutrient.

    I am also playing with a mix of Coir and the local mountain moss, with additions of the above, in various combinations.

    I am not a chemist but I am fairly savvy. I need to build in some buffering to try to stabilize the nutrient mix at about pH5.5. The fungi can get out of hand very quicky here.

    The big boys like General Hydroponics claim to have well buffered mixes, what are they doing to get this?

    Can I add one of the triprotic, weak acids and play it off against one of the tribasic, weak bases?

    Hard water with its carbonates and bicarbs has some (non-plant active) buffering ability. Could I add one of the non-sodium carbs or bicarbs?

    Is there some way I can mix and match constituent chemicals to get them to play buffer at around pH 5.5, or will I have to resign myself to the continous adding of acid?

    Thank you

  2. jimmyq

    jimmyq Well-Known Member 10 Years

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    Metro Vancouver, BC, Canada.
    With hydroponic nutrients each component is taken into consideration when manufactured, each component will have a measured, direct result on the nutrient solution. Each nutrient will react with one another potentially with pH adjusting results. Calcium is used as a buffer in many dry mixes and some liquid nutrients but, keep in mind that some nutrients will snowflake (precipitate) as a result of mixing with other nutrients in concentrated form. Hence, always mix your nutrients in your final volume of water and use room temperature water. Using a small volume of water to mix in, usually hot water, is not a good idea as this will potentially cause such reactions (precipitation). Flushing your solution regularly will also control pH, the longer a solution is left to evaporate with nutrients dissolved, the greater the chance the pH will lower due to those nutrients. Most plants would prefer pH about 6.5 or so for optimum broad range nutrient absorbtion, there are exceptions of course. Measure the pH of your source water regularly, get your water tested for mineral load regularly so you can establish average values and then you can begin the calculations regarding nutrients that you need to add and the ratios that will be beneficial. pH control in this market is usually phosphoric acid or nitric acid for acidifying and potasium bicarbonate and/or potassium hydroxide for raising the pH (alkalifying? :) Hope some of this helps.
  3. about drip irrigation and mediums

    Hi! I am a student from the philippines, we are conducting a feasibility study about Hydroponics. I would like to ask, in planting bell peppers or capsicum, they say that the drip irrigation system would work best, can you tell me its advantages and disadvantages? and How should I set up a system like that for a 700sqm. land? What are the materials and equipments needed? and they also say its best to mix coco peat or coco dust with rice hull.....what is the role of rice hull as a medium? thank you very much. i hope you can reply in the soonest time possible!

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