General Yield Question (about # of grams per watt) - Not the typical yield question

It's generally acceptable that if you end up with 1 gram per watt then you had a good grow...Question - Is this per plant, per square foot or what? For instance, I have (4) 600 HPS lights in a 4x12 area....I have 23 plants under them and each plant is between 3-12 inches from the light....I'm just using mine as an example but with 2,400 watts, should a person expect 1 gram per watt total for all of the 23 plants or is that amount counted assuming each light gets 4 plants and the 1 gram/watt is for the total of 4 plants....

Not sure if this is clear but I think it should be...The gram per watt calculation is done using how many plants per light?

To make my question more clear - would you get 600 grams if you had 1 plant under a single 600?

It's per light, you have 2400 watts so if you are shooting for a gram per watt you should end up with 2400 grams total from all 23 of your plants.

I dont go by the gram per watt. I have 4 1000watt hps and pull close to 5 pounds with 36 plants

Banditt said:

It's per light, you have 2400 watts so if you are shooting for a gram per watt you should end up with 2400 grams total from all 23 of your plants.

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That's what I was thinking but then what's that magic number where it doesn't matter how many more plants you have under it? Is it 5 per light? 8 per light? and it it's per watt total, why can't you get 600 grams with only 1 plant under a single 600?

I been thinking about this and thinking of different scenarios and they all seem right, that's why all the questions...Also because I hadn't seen anything that answers this specifically....but thanks for the replies

its not about watts its about area. for example 1,000 watt covers a 4x4 area. why put one plant under it and expect 1,000 grams when you can put as many plants as the light covers.

OZUT said:

That's what I was thinking but then what's that magic number where it doesn't matter how many more plants you have under it? Is it 5 per light? 8 per light? and it it's per watt total, why can't you get 600 grams with only 1 plant under a single 600?

I been thinking about this and thinking of different scenarios and they all seem right, that's why all the questions...Also because I hadn't seen anything that answers this specifically....but thanks for the replies

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Theres a lot of variables involved. Like MrStickyScissors said the area your trying to cover with your light makes a difference, as does the amount of canopy the light has to penetrate etc. Too many plants and you'll reduce your yield because the plants will be blocking out each other's light and choking each other. Not enough plants and you will have wasted light also reducing your yield. Grow the plants too tall and light won't penetrate down far enough. So the amount of plants you are putting under your light is more less dictated by your space and how large you want to grow them out. I wouldn't worry too much about the gpw figures, it's more just a baseline for estimating potential yield. Some people pull .5gpw some pull 2gpw. Just worry about growing the best shit you can in the beginning.

So... for 240 plants using 2x 1000w bulbs... 2000g (4.4 lbs) is a good goal? Damn that seems like a lot. Is that dry weight?

aficionado said:

So... for 240 plants using 2x 1000w bulbs... 2000g (4.4 lbs) is a good goal? Damn that seems like a lot. Is that dry weight?

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I'd like to see you get 240 plants to fit under 2 1000w bulbs.

Exactly, I think it comes down to how many you can comfortably put in the area but that 1gram per watt goal everyone always mentions always had me wondering

It depends on far more than light.
You can get 1g/w (even more, far more) if you got everything right.
Basically this applies to a SOG if all conditions are optimal, you should get close to it.

Look it's simple, that whole gram per watt thing just means that if u set up every other variable correctly, meaning light proximity to the plants, temperature, nutes, watering, everything else was good, then u SHOULD get around a gram per watt... If u do certain things to get more than that then ur doing good! For example look into VERTICAL growing. U can get up to 2.5 grams per watt of light used

Not to mention the biggest variable of all... GENETICS.

i was once a grower of a few plants eg,4 under 1 x 600 hps.
but since moveing over to useing more lights and less plants,i have had great yeilds
best to date is 28 1/2 oz from 2 jack herer plants grown under a 600 hps each
14 and a 1/4 of each plant,has made growing far less stressful with the problems with the beast man.
i have just started a 6 plant blueberry grow in a 16 ft x 16 ft x 12 ft height
im using 6 x 600 hps lights 12 " out let and a 8" inlet there looking the biz,and loveing the room
i do not bother with ph even though im useing a old school hydro set up auto pots,with air rings in the bottom of each pot
just a simple fish pump run to two pots,so a total of 3 pumps.
nute wise canna a/b all the way through the grow but ec set higher each week i have tried many differant feeding sceds but,i have at last found what i think is the one for all the strains i like,mind you thats just 2 jack herer and blueberry.The bluelab trunchen is has important has the lights so do away with the ph meter and get one unless your water is not good.i have no co2 burner just good north fresh air on the intake.
here is the grow sced if any one is interested you will not be dissapointed,has long has the lights are set at the right height and you do not over do it on the amount of plants.from getting a clone either one you have done your self or bought in,i would advice getting into cloneing because it takes away the risk of sick plants but more important other people knowing what your doing,once the clones have got legs[roots] then put them into the next size cube,then wait till there is a good root set.if you take these 4 weeks before the end of a grow then your ready to go again.
week one,
place the clones into the medium i like clay balls and coco but choice is yours
water once a day just around the base of the stem if growing in hydro,the idea of this is you want the roots to reach the bottom of the pot has fast has possible so you can put on the tank.
canna coco a/b and revive or any transplant nute good for first few hand waters.
for the 1st week 1.1 ec
week two
canna a/b up the ec to 1.2
week three
canna a/b 1.3 ec
week four
canna a/b 1.4.
by this time the plants should be around 2 ft tall.

flowering phase
week 1 canna a/b 1.4 ec
week 2 canna a/b 2 ml per ltr of big bud from advanced for one week 1.5 ec
week 3 canna a/b
week 4 water for 2 days then back to canna 1.6 ec
week 5 canna a/b and pk 13/14 at dose stated on bottle,for 4/5 days the pk 1.6 ec
week 6 canna a/b 1.6 ec
week 7 canna a/b 1.6 ec
week 8 water for 7 days.
hope this helps