Well the plants seemed to have responded well enough with a uniform healthy looking green. I mixed 36g Jacks, 24g CalNit and 11g of epsom with 1 litre of water each in separate pickling jars. I then took equal measurements from each jar with a syringe, adding it to my tap water (ec 0, ppm 500/ 40, ppm 700/60) until the solution was EC 1.2, ppm 500/630, ppm 700/860. Came out at exactly ph 5.6.
While mixing everything up I got to wondering how much I was actually saving on nutes and to be honest I'm underwhelmed. The numbers are not scientifically accurate, but they are accurate enough for me and thought I'd share.
The small stock with 36g of jacks will do approx 8 gallons of nutrient at EC 1.2. In a 24lb bag there are 10,886g which is 302 batches. This makes up 2419 gallons of nutrient solution (with cal nit and epsom still to be added)
I was running GH flora series with cal mag.
To achieve 1.2 EC nutrient solution of equal measures of Jacks 24lb bag I'd need: (bloom and gro switch quantities when I flip, but keep it simple)
Flora gro - 3 ml per gal = 333 gal per litre bottle. 2419 / 333 = 7.2 litres of gro needed
Flora micro - 2 ml per gal = 500 gal per litre bottle. 2419/500 = 4.8 litres of micro needed
Flora bloom - 1ml per gal = 1000 gal per litre bottle 2419/1000 = 2.4 litres of bloom needed
Cal mag 2ml per gallon = 500 gal per litre bottle 2419/500 = 4.8 litres of cal mag
I also use
Floralicious plus - 1 ml per gal = 1000 gal per litre bottle 2419/1000 = 2.4 litres of Floralicious
Silica - 2 ml per gal = 500mgal per bottle 2419/500 = 4.8 litres of silica needed
Over all if I was to buy GH series I'd pay; (Individual unit cost x litres needed)
Individual litres:
Gro - 8.95 x 7.2 = 64.44
Micro - 8.95 x 4.8 = 42.96
Bloom - 8.95 x 2.4 = 21.48
Cal Mag - 18 x 4.8 = 86.40
215.28
Bulk (per litre of 5l):
Gro - 5.59 x 7.2 = 40.25
Micro - 5.59 x 4.8 = 26.83
Bloom - 5.59 x 2.4 = 13.42
Cal Mag - 10 x 4.8 = 48
128.70
I'm not going to add silica to the list as I'll be using it with jacks so not making any saving there. I won't include floralicious plus or rhizo either as they're a different kettle of fish I'd say and will probably still use them, well definitely still using rhizo as I've just transplanted young veglings
I paid 150 shipped for the jacks alone so I'm actually down 30 if I was to buy GH in bulk and made like a 50 saving from buying individual litre bottles, but this saving is made after using 2419 gallons of feed.
I haven't included bloom boosters . However, cal nit, epsom or mpk are not accounted for in the total for the jacks mix, never mind adding any micros. But as I said it was really just to give a rough idea, I soon realised there wont be olympic swimming pools worth of feed in savings as previously mentioned in this thread.
It certainly wasn't worth having fertilizer shipped from the US with hydroponics plastered all over the box, which is probably unfinished and lacking in micros needed for cannabis, according to some anyway.
Obviously others using jacks will have different needs from my own, but thought I'd share as there may be someone lurking in the EU wondering if it's worth making the leap and getting some imported. It's easily to get excited without properly thinking it through.
I'm hoping these numbers are massively wrong and there's a 0 or two missing in jacks' favour but I can't see it. Someone prove me wrong please, no really.
