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Man... Let me tell you my story - yield and grams per watt

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Keeping to whats relevant... I lived in England from 2000 to 2005. I stopped smoking for a while but decided to start again after a year or so. I asked a friend at work to sort me out an ounce. He said, "Sure, come round my house". I popped round, he said here's your ounce and take a look in my loft / attic. He had a 3.5x.3.5m room full of it, 2x days away from harvest. 4x 1000w hps, 4x girls under each, 1.2x1.5m per light per 4x plants. I had never seen that before, very very impressive, something nature won't do on her own.


I had just bought a house and my friends suggestions was... "Get it going in your place", my response was "**** yeah!". I gave him £2,000, he bought all the equipment and consumables, came to my place installed it all, gave me clones, showed me everything.


(long time ago, now i don't re-call everything perfectly). Pots had layer of hydroton at the bottom, rest was 50/50 coco perlite. Canna A and B Flores i think was used, with PK13/14 and the Hydrogarden Dry Flower 4x part range of additives.


Pots were placed in trays and bottom fed. Strains i believe was white rhino and mother's finest, (from sensi, i think). I see mother's finest is sensi, so i assume the rhino was from sensi too.


Anyways, 4x week veg, 8x week flower, 1000w 4x HPS, 16x plants, 1.2x1.5m space under each light, 4x plants under each, and... it came out at about 4.2kg each time, a little over 1 gpw.


Imagine... You bumped into someone who showed you / gave you all of that!!


Anyways... in 2006 i moved to South Africa, Johannesburg, (many reasons). I decided growing was not a career move, i wasn't going to do it again. There's plenty of outdoor in Africa, why bother.


However... in 2010 i decided i needed grow again, (many reasons). So...


I went about setting things up as closely as i could to what i was shown in the UK...


15L pots filled with 50/50 coco perlite, bottom layer of hydroton, 4x under a light, plenty of space, 1.2x1.5m per light, per 4x plants. Canna nutes aren't available in South Africa so i've ended up using GHE, Lucas formula seemed to work best.


Since 2010 i've had many trials and tribulations... First thing i found out was the canna coco we were using in the UK is PH corrected, but at least now i know to Ph correct the medium before use.


Basically... since growing in Johannesburg I've been getting a pretty consistent 0.5 grams per watt... Half of what i was getting in the UK.


I have been trying everything i can to improve this and get it back to what i was shown in the UK. Johannesburg is 1,600m above sea level... This is the one variable i cannot change.


Otherwise i have... 3200w, (2x 1000s and 2x 600s) 16x pots, 4x under each light, 50/50 coco/perlite, layer of hydroton, GHE nutes using Lucas formula, all air cooled reflectors, temps 22 to 32 celcius, big mist maker and humidistat, 40% humidity. I'm using phillips 1000w hps bulbs and 600w sun masters, lights are the same as UK, humidity is the same, temps are the same, medium is the same.


Selection of strains... white widow max from marijuana-seeds.nl chronic from seriousseeds.org, super sk from a friend, most recently and not yet flowered, white rhino and white widow from green house seeds, and liberty haze, pineapple chunk, grape ape, critical kush from barney's farm. The chronic i bought 20x seeds and only kept the best 2. All seeds i've bought recently i will only keep the best 1-2 of 10.


I have never gotten more than 1.6kg from 3000w in Johannesburg, where as it was 4.2kg from 4000w in the UK.


Basically, i'm asking / pleading for someone to tell me / advise me... where am i going wrong? Been 3x years now, many cycles and haven't significantly broken the 0.5gpw figure.


Strains are different, but i have tried a few now and all come out around 0.5gpw, so i'm not sure if its strain.


Nutes are different. GHE Lucas now instead of Canna, but i bought load of aditives, GHE bloom and root boosters, canna PK13/14 imported, even imported the dry flower 4x part program... none made any real difference


Altitude is different, Johannesburg is 1,600 meters above sea level, UK is at sea level.


I've let the plant get too big sometimes and end up with a lot of wastage on the lower branches, this time i'm flicking smaller.


I phoned the guy who showed me it all, he moved to Australia, doesn't do it any more and could not really tell me the secret, (i'm not sure he knew himself). I called the grow shop in the UK we were using, but they point blank refused to say anthing on the phone. I'm posting this on a lot of forums in the hope of getting the "silver bullet" answer, or even pointed in the right direction would be good.


It was so easy in the UK, it just happened, 4kg every 3x months, 1gpw, but... now i'm struggling for years and don't know why.


I'm going try with the latest seeds i've bought, GHS WW and WR, and Barney's Farm, range of 600g per m2 strains. If i still get the same result with them i suppose i will fligh to Amsterdam and buy Sensi White Rhino, (they don't ship to South Africa).



Anyways... If any of you ever wondered is 1gpw possible, answer is yes definitely, the first 4-5 grows i did i got that, under some expert tutorlidge in the UK with Canna nutes, but...


Now in Johannesburg with GHE nutes, Lucas formula, all of the above, i simply cannot get more than 0.5gpw.



This is having a bad effect on my life in general. It may be a "dependant arising", but... dam! i have to get it back to 1gpw.



Please, please, please... any good advice is very much appreciated, (only respond if you know wtf your talking about, there's millions of punks out there with different stories), if your not getting around 1gpw you may be one of them.


Responses from those who know what they're doing are highly appreciated.


Thanks in advance

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Do you think the higher altitude may have something to do with it causing a lack of co2. Maybe pumping some co2 into the room may help.  


First I should tell you I could be a punk cause I don't get over 1 gram per watt.


The variation in CO2 concentration as a function of altitude varies by less than 5% up to an elevation of 4000 metres. Not enough variation imo to account for your variation in yield.


Naycha :peace:

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Cannabis actually does well at higher altitudes, so don't think its that. I constantly hit 0.7g per watt or slightly more, but thats nowhere near as many watts as your using, I have like 5-6 plants per 600wer.

Hope you find ya problem, I'm kinda headin with bricks theory. I had opposite, cold that affected yield, this run, fewer plants, but better looking buds using a heater lights off.

Heat can be a killer inside when it comes to yield. I always found I got better buds in slightly cooler temps. Are you using CO2, because if your using same amount of light you used in England, you should be.

Oh, and welcome =)


Peace. Nibbler

Edited by The Hash Nibbler
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Root oxygen
Tried with air stones in the pots... f all difference

Lucas compares nutrient profiles

I've tried different nutrients and additives, Lucas with .pk13/14, hydrogarden dry flower 4x part program. Food grade humic and fulvic. Www.gthydro.co.za nutes custom made. Admittedly I've not bought the canna flores A&B. Perhaps I'll import canna A&B, .pk13/14, dry flower 4x part mix just to be sure, but... tried different nutes and, honestly... none of them made f all difference either way.

M12 mist maker and humidistat... johannesburg is dry. UK is humid. Bought a BIG mist maker can have many humidity whatever I like, outcome was.... humidity makes f all difference... 10% or 60% or anything in between same result, (no humifier in UK)

UK wing reflectors , not air cooled. Ran portable air conditioner / fan assist heater. UK temps were 20-36 celcius. Johannesburg I've air cooled reflectors, need to be more careful with power consumption... Johannesburg temps also 22-35.... more stable that UK.

Air flow.
Room 3m x 3m x 2.5m high. Used top run 2x 500m cubic meters per hour fan for extracting through air cooled reflectors. Now just using one as two suck out the humidity too quick. Have some intake fans too but only run them if it gets hot.

I keep mothers and I clone. I select best 1-2x plants from seed and keep mothers from them only.

Bought an ro filter... made f all difference. They prefer tap water. 0.2 .ec in straight tap water here

Good comments have been made about:

Pruning and size when flicked - appreciated
Altitude - appreciated
Nutes - better just import the canna to be sure
Strain - appreciated

I think the lack of "the simple answer" speaks more than the given answers.

The man who said, in different words... "just keep trying with different strains and plants and you'll find a good one sooner or later"... was probably the best answer.

Also... someone on thcfarmer said I was lying.... hahahaha.... if that's what you think, imagine what I think !! ... did I dream those years? Is this life actually real at all ?? What is it trying to do to me ??

Anyways... sooner or later I'll figure it out... different strains and plants, canna nutes and a trip to the dam to get sensi seeds.

All prior and future comments appreciated.

I'm very busy but may post some updates and pics.

Not keen on co2

Thank you all. Thanks

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It doesn't matter where you are in the world really, indoor growing will work the same everywhere as its a controlled environment that replicates the best nature has to offer.  Indoor setups can easily be replicated as all the equipment is mass produced, the plants you grow are a different matter entirely though.  You'll never be able to get the same plants back even if you grow seeds from the same batch of seeds the original plant came from.  Your only option is to buy more seeds and stop thinking like a commercial grower.  Obviously yields are very important but if you can't get enough for self supply with 4000w you should move outdoors.  I've calculated that I could do 4-5 pounds every 2 months if I were so inclined from 2200w by having 16 plants per light that have been vegged for 2 weeks.  I was getting 1.5oz per plant on average growing like that in the past but the plant numbers to achieve such a yield in such a short period of time is insane and with no commercial interest in cannabis its not worth the risk to me.  It might be worth the risk to you but I would recommend going outdoors over higher numbers indoors.

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