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What do the three numbers on the fertilizer label stand for?

Smokin Moose

Fallen Cannabis Warrior
Most people believe N-P-K to stand for the nitrogen, phophorous, and potassium, but that is somewhat incorrect. These are commonly referred to as the major elements along with calcium, magnesium, and sulphur. They are the major contributing compounds in plant growth.

N: nitrogen, used to stimulate new vegetative growth and overall health.
P2O5hosphorus oxide, used to stimulate flower development and rooting.
K2Ootassium oxide, used to stimulate stem growth and overall health

N-P-K ratings on the labels of fertilizers are misleading at best. They represent N: nitrogen, P2O5hosphorus oxide, and K2Ootassium oxide. These molecular compound ratios are not the same as the elemental ppm of the associated primary element, except in the case of N. They are only the guaranteed minimum amount of the molecular compound.


For example:

A fertilizer labeled 30-10-10 can have up to a total of 80% N, along with 10% P2O5, and 10% K20 and still be "accurate". It could have any combination of N, P2O5 and K2O adding up to 100%, as long as it has at least the MINIMUM listed of any of the three. You could have 50% nitrogen in 10-30-20. These types of labels are misrepresentative. Anyone using them to establish a controlled nutrient balance is not doing their plants any service.

As a general guidline, the N-P-K numbers can be roughly converted to elemental ppm. N, nitrogen is the only element to convert from the label at the ratio of 1 to 1. P2O5, phosphorus oxide, converts to elemental P, phosphorous at a ratio of 1 to .4. K2O, potassium oxide, converts to elemntal K, potassium at a ratio 1 to .8. This demonstrates the radical difference between an N-P-K of 1-1-1 and an actual elemental ratio of 1-.4-.8.

I have only found Botanicare and Green Air Products Genesis nutrients to give the actual ELEMENTAL ppm after dilution. I used to mix my own solutions from ammonium nitrate, calcium nitrate, magnesium nitrate, potassium nitrate, potassium phosphate and other reagents and know from nutrient analysis of the misleading nature of N-P-K labels.
 

hashishan

New Member
do you know any brands of fertilizer at home depot we could get?
 

Cherma

New Member
Happie, we need Racefans ear on this one,my experience has been soil grows. Hit search though and check out the Hydro section grows. Also for now see below on the links.
I will be back and over to there and see what comes up.
 

happiehippie

New Member
Happie, we need Racefans ear on this one,my experience has been soil grows. Hit search though and check out the Hydro section grows. Also for now see below on the links.
I will be back and over to there and see what comes up.

Het man thanks, will do. :48: :51:
 

Racefan

Well-Known Member
Cherma...whats up man. I am doing a 5 gal. hydro with drip and air stones. I realy need suggestions on what too use, this is my first shot at liquid ferts. any help would be greatly app. Thanks for your time man.
:48: :hippy:
It really depends on where you shop as to what to use. any water soluble nutrient will work. Some just work better than others. I use a nutrient called "pure blend pro". There is one bottle for the vegetive or "grow" phase and one bottle for the flower or "bloom" stage. Some like to use the general hydroponics flora series nutrients but it is a 3 stage mix per stage. What i mean by that is that for "all stages of growth you mix all three nutrients together into a reservoir. How much of each bottle is determined by what phase your growing in. The nutrients are micro, grow and bloom. IMO they are great nutes but really easy to screw up. Try to get a one stage nutrient that requires one bottle for grow and one bottle for bloom. powders work as well just disolve them into warm water than add to your reservoir. You need a PPM or ec meter for hydro as well as a way to measure ph. You need a way to lower ph as well.
 

happiehippie

New Member
racefan.....thanks man, you always have the good info man!!! I will deffenatly look into the one bott. for grow and one for bloom like you said, les chanche of me screwing that up. Keep the info smoking...I mean comming in man!!!
LETS SMOKE........... :48:
 

Cherma

New Member
Thanks Racefan,
Some like to use the general hydroponics flora series nutrients but it is a 3 stage mix per stage. What i mean by that is that for "all stages of growth you mix all three nutrients together into a reservoir
. I have heard from several other growers I know that this can be a bugger and tempermental.
 

Tony614

New Member
I've heard from a few buddies that less is more. Would keeping plants healthy while using minimal nutes still give a good, healthy plant? I just want the tastiest buds, but not at the expense of the health of my babies.
 

420pharms

New Member
Okay, so if N-P-K is not accurate on most fertilizer's then how do I get the ratio that I may want, say for example I mix G.H. Micro 5-0-1 and G.H. Bloom 0-5-4 in equal amount 1ml to 1ml into a gallon of pure water and I think it's N-P-K is 0.5-0.5-0.5 by using the #'s on the label. Do I use the elemental multipliers ? I currently use the N-P-K values stated and test TDS strength with ppm @.5scale. I am very tired of all the mistakes that I have made due to lack of understanding and misleading information. It has been a good scam for the Hydroponic industry and those who are internet heroes with no or low actual horticultural skill who just want to enlarge their ego. I try too keep it in the spirit of having fun and that it's a toy not a trade, but I find that I am giving advice and not getting any back and that I may have good results. I know I don't Know much about plants, I wasn't born a farmer and most farmers don't spend the amount of $ or time per plant I have nor do they know as much about their plants and nutrition. they work hard long hours just tending their fields and trying to keep operational cost low I think that Fuel seed and labor is their largest cost. For me the cup winning seeds obtained from breeders have been a fiasco at best and my fertilizer cost has competed with my electricity cost. It's not cheap to grow in a full sealed co2 enriched air conditioned space. It's a toy more for popular science or NASA than gardeners digest. If you can help me get N-P-K value correct I would be very very grateful
 

QuincyGrow

New Member
i am sorda a first time grower first time being very serious about it before i was just a idiot trying to grow weed to show off to my highschool friends haha but i really would like to know at what times u will want a high N a high P and a high K for your plants and also what should i be giving to my organic outdoor seedlings that will not burn and just help set myself up better for my future harvest any advice would be amazing can someone plz help me
 
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