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Nitrogen Phosphorus Potassium (NPK) ratio's - What ratio's work best for cannabis?

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    HYDRO Nitrogen Phosphorus Potassium (NPK) ratio's - What ratio's work best for cannabis?

    Hi fellow hydro (and soil/coco) growers,

    TL;DR: What ratio of NPK do you feed your plants? How did you measure it?

    Been doing some reading and research into NPK ratio's for growing cannabis, and have only found varying guidelines for the stages of seeling/vegetative growth/bloom periods.

    On https://www.growweedeasy.com/best-hy...ients-cannabis , there is a general recommendation:
    Optimal Hydroponic Cannabis N-P-K Nutrient Ratios
    Life Stage N P K
    Vegetative/Grow High Medium to High High
    Flowering/Bloom Low High High
    Nitrogen (N) behaves as is, NPK of 5-0-1 (Flora micro) will give 5 N.
    Phosphorus (P) and Potassium(K) are different.

    Nutrients will show on the label - Available (P2O5) for the amount of phosphorus and (K2O) for potassium.

    From: https://www.maximumyield.com/what-s-n-p-k-anyway/2/1220
    "The problem is that the N-P-K labeling for the product does not show the actual concentration of these elements themselves (P or K only), but instead gives credit to the attached oxygen molecules.
    For reference, the elemental concentration of phosphorus is 43.6% of what’s labeled and potassium is 83%."


    Typically,
    NPK Ratio N P K
    Micro 5 0 1
    Gro 3 1 6
    Bloom 0 5 4
    For equal amounts of micro, gro and bloom (1.25ml) would result in a NPK ratio of:
    N P K
    2.7 2.0 3.7
    If I take into account the elemental concentrations of NPK that are really there, it looks like this:
    N P K
    2.7 0.9 3.0

    My question to you growers is:
    - what ratio of NPK do you feed your plants?
    - How did you get to that ratio?
    - what amounts of NPK do your nutrients have on the bottles?


    You can use the attached NPK calculator spreadsheet. NPK calculator - Copy.xlsx
    Its based on Flora Micro/Gro/Bloom but you can modify for your nutrients.
    Attached Files
    Lighthouse LITE growtent 1.2m x 1.2m x 2m
    PLANTiT DWC Aeros IV -> 4 buckets + main tank [75L total volume]
    Budmaster G.O.D-4 LED light (their recommended replacement for 400w HPS)
    RAM air blower with carbon filter
    Hydor Pico 600.115 600L/hr water pump
    2x Marina 200 Air Pump (2X110 L/hr) to 2 air stones each
    Hydrogarden ESSENTIALS pH Meter
    HM Digital (NaCl calibrated) TDS meter

    #2
    I just follow the instructions for Botanicare nutrients at half strength and it works great.
    Unless you are trying to make your own batch.

    Comment


      #3
      NebulaHaze , SiriusFourside I hope you might be able to give some insight.

      For context, the feed schedule I'm refering to is this one: https://www.growweedeasy.com/sites/g...t-schedule.pdf
      It's for Recirculating Nutrient ScheduleGeneral Hydroponics Flora Series + CaliMagic.

      The PDF above uses teaspoons as measurement, 1 tsp = 5ml.
      A while back I made the chart below to help me with the amounts I need for my used water (showing a volume of 10 gallons as example).
      Only recently I added the NPK ratio's to the right (those are not adjusted for actual P and K present)

      Click image for larger version

Name:	GWE Schedule - GH +strength + NPK ratio - 10Gal example - Copy.png
Views:	2
Size:	125.6 KB
ID:	305055

      When you adjust for P and K availability, 43.6% P and 83% K, the ratio's for P and K are lower.

      See below when adjusting for the availability:
      Click image for larger version

Name:	GWE Schedule - GH +strength + NPK ratio - 10Gal NPK adjusted - Copy.png
Views:	1
Size:	87.9 KB
ID:	305056


      One would think, to increase the P and K ratio, you'd have to add more Bloom (0-5-4), but that changes the ratio's of N as well.
      It becomes a balancing act to find a 'sweet spot' for NPK ratio based on the amounts of Micro/Gro/Bloom you add to the mix.

      I suppose this goes for any nutrient mix you use from any nutrient company.

      As such my question: what's the best ratio for N-P-K to grow the plants we do?

      for seedling/vegetative growth/bloom periods.

      Thanks for your insight!
      Lighthouse LITE growtent 1.2m x 1.2m x 2m
      PLANTiT DWC Aeros IV -> 4 buckets + main tank [75L total volume]
      Budmaster G.O.D-4 LED light (their recommended replacement for 400w HPS)
      RAM air blower with carbon filter
      Hydor Pico 600.115 600L/hr water pump
      2x Marina 200 Air Pump (2X110 L/hr) to 2 air stones each
      Hydrogarden ESSENTIALS pH Meter
      HM Digital (NaCl calibrated) TDS meter

      Comment


        #4
        i think you are overthinking it, the exact nutrient requirements will change according to the water you use, your environment, the light source, the set up (hydro) or soil contents and most importantly the strain. those numbers are just a guideline to know where to start and with some practice youll realize as long as you are providing enough without being too much the plants will do fine. you may try different nutrients and some will work better than others for you, this doesnt mean theyre the best, thay just work for you. i use botanicare too, its only a two part (grow & bloom) grow has lots of nitrogen and bloom has lots of PK
        current grows
        https://forum.growweedeasy.com/forum...-coco-question
        https://forum.growweedeasy.com/forum...picture-update

        Comment


          #5
          k i s s ….
          "Treachery and Old Age will overcome Youth and Skill"

          Current grow. All hermied seeds.

          1 Purple Kush (5 year old seed)
          1 Somango (1year old seed)
          2 unknown (6 year old seeds)
          2 Black Jack (2 year old seeds)

          Comment

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