Fertiziling with in-organic salts..

Discussion in 'First Time Marijuana Growers' started by Kesey, Aug 21, 2016.

  1. Inorganic salts from my experience are an effective and rewarding method of cultivating cannabis..but not without the proper techniques..

    So here's my guide to mixing a reservoir to start..

    1. Application Rates: So for the sake of explanation lets say you're using branded fertilizer from the grow store..lets say a 2 part regiment (Generally one for flower, one for the vegetative stage). We'll use the 'veg' in our example and lets say the combined npk values = 7-2-4. So this is the ratio you're using at their recommended application rate..now when you hop on the forums and read others advice they'll more often than not recommend adjusting your feed (In hopes to correct a deficiency, usually)...''try 3 ml/gallon instead of 5''. When you do this you're not adjusting strength..you're adjusting the ratio..due to elemental weights; adding additional elements do not scale with each other..

    To achieve strength of solution you need to adjust the concentration of the fertilizer by adding/removing volume. This is done by adding water..

    2. Mixing the reservoir: I've got my 7-2-4 veg fertilizer and lets say the recommend rate is 2ml per bottle (always applied in equal amounts) so effectively 4ml total. So in a 5 gallon reservoir I'd start with the fert bottle that has highest amount of calcium (9 times out of 10 its part 'A'). I'm doing this for 2 reasons; I'm assuming reverse osmosis water is being used (Which is extremely unstable with Ph fluctuations)..the nitrates will help to with this and the calcium going in first will avoid chance of precipitation (elements binding, particularly calcium ----> sulfur and potassium -----> sulfur. Basically don't add 'Part B' until you've reached a stable Ph (5.8 in coco, 5.5 in hydro, 6.5 in peat). The #1 culprit for precipitation is potassium silicate...if using silica its best to apply it as Ph up in the reservoir initially and allow it to dissolve well..if using a calmag product be sure to add it after the 'veg' fertilizer or you will cause preciptiation with potassium binding calcium. It's assumed adding silica first will raise ph...followed by part 'a' the ph will drop and buffer itself and ph swing should not be an issue..

    <RO Water> - Silicate - Wait 30 mins - Part A - Wait 1 minute - Part B - Wait 1 Minute - CalMag - Wait 1 minute - 'boosts' (lol..)

    Now say this is our recipe..it's go the elemental ratio we want, any additives, etc etc etc..now say it parts per million = 1000 (@.5 scale, some meters are different...be sure to identify which scale yours meter is using). This is obviously too strong for a seedling or fresh clone..

    So instead of 'trying 1ml instead of 2ml' we're going to add more water to our reservoir (so say you plant to mix a 5 gallon res...you'll need a 10 gallon+ in reality,,,eventually you'll work out how big of a res fits your needs)...our 5 gallon res has a PPM of 1000 and then we add 3 more gallons of water...dropping the PPM to 400 and a suitable early veg strength. We did this while maintaining our elemental ratio (which we tailored specifically for a certain strain of cannabis) and avoiding both elemental 'lockout' (because our ratio was appropriate...N > P > K > Ca > Mg for peat and hydroponics N > P > Ca >Mg > K for coco (Coco is naturally high in potassium and as such require a different ratio...(Catching on yet? ;) ). Always being conscious of our K:Ca:Mg ratios as any problems here will result in zero uptake (Imbalance in the cation exchange (+1 elements).

    If you have any questions or if I was poor at explaining something just ask I'll do my best...

    Have fun and be safe :)
     
  2. Two factors will dictate your feed strength; strain and environment.
    1. Strain is pretty obvious...certain strains want certain things, this is where skill comes into play and takes time to acquire, simple as that.

    2. Environment: Lighting conditions are the #1 environmental factor. This includes wattage, lighting type, effectively distributing it on all plants, Day/Night cycles. Too strong of a light is counterproducive; increased nutrient requirements resulting in nutrient burn particularly early on. Likewise a light that is too weak requires less nutrient requirements ultimately removing the benefit of inorganic salts in the fact that they can be fed frequently and constantly uptaking. Even the same strain in the same room will do different if the lighting is poor...a plant that is shaded or far from the light will require less nutrients than the ones closer to the source. Obviously a plant under 24 hours is going to feed more than a plant uner 18 hours of light...but theres static way to approach this. Instead, you have to take these factors and use them to your advantage...starting early veg under 18 or less so you can feed less often (the frequent waterings come when an established root system is ready) and avoid overwatering (The best mix is coco and aeration mixed 1:1 for this reason, imo at least) then when you have more established plants you can go 24/0 and really push em without creating poor pot condition or over/under fertilizing...so say you feed an early veg @300 PPM...you can continue to feed at @300 for the remainder of veg but now just increase watering rates (drip fed 3x a day is a good goal to reach). Experiment with different concentrations (Read first post) until you dial it in..

    The other environmental condition to watch out for is VPD or your vapor pressure deficit. This is basically the pressure in the room affecting the surface of the leaf....a high vpd will 'suck' water out of the leaves...now the plant takes in more water because its pretty much being sucked out down to the roots...along with the water comes the inorganic salt and this can lead to overfertilization. Strongly recommend balancing 3 factors.. airflow/ventilation (intake = outtake) and then temperature in relation to humidity. A low humidity and high temp = high vpd, high humidity and low temp = low vpd...high vpd the plant is taking in too much on its own...low vpd and over fertilization is caused by strength of solution (high ppm). Again, this is manipulable...you can really push your pants with some frequent waterings and high vpd...but backing when you start to burn....ya dig? All of this is to be used and catered to your individual conditions..
     

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