The idea behind 1 gram per watt

When people say a gram a watt.. how are they determining the gram per watt?

What I mean is.. what veg time and flowering time = 1 gram a watt?

for example, We all know that if a person were to veg 12 weeks and flower for 10 weeks, they should easily come up with a gram per watt with a 250hps.

We should come up with something more accurate... any ideas?

My guess is grams per square inch by the time it takes from seedling to harvest.

Lighting is a huge factor for yields. Sure other factors certainly play a role in making a harvest poor or excellent (genetics, water, pH & nutrients, temperature, ventilation/carbon dioxide concentration, vegetative period, proper container size, and minimizing other negative stresses such as pest infestations), but lighting is huge and indoors we need lighting that is both of the proper spectrum and intense enough for our plants to thrive. When all other conditions are perfect, your yield is essentially going to be determined by your lighting. Thus the best way to predict yield or help foster garden efficiency is to consider the amount of energy being consumed for lighting.

If you're getting about 1 gram per watt, your methods and plant health are likely exceptional. If you're yielding much less than that, something might be off and there is very likely room for improvement. If you typically yield a gram per watt, or otherwise are aware what you typically yield then you should be able to predict your yields even if you change your lighting.

The amount of space plants are being grown in matters much less indoors, so long as there is enough space. At any rate it can't really be used to determine yields like lighting can. If you have six plants growing under a 400 watt HID in a 3x3 room, or six or more plants in a 4x4 room under that same 400 watts: the yield should be about the same or less. Of course, if you keep expanding the space and/or number of plants without also increasing lighting your yield will only decrease as that lighting is forced to cover a larger area, becoming ever less intense. Therefore lighting is a much better indicator of yield than space or number of plants.

When trying to determine the amount of lighting to provide for x amount of space cannabis likes between 30 and 50 watts HID per square foot (anymore and CO2 supplementation is advisable, plus increased water and fertilizer). So a 400 watt HID is perfect for a 3x3 (9 sq ft) area or no larger than 4x4 (12 sq ft) area. You will get more yield per square inch in the 3x3 space than you would in the 4x4 space, but over all yields should be about the same. Hope this helps.

im order to get 1000 grams in 1000w hsp ( 1 gram per watt) you need a plant that has the potential to grow 1000 grams within within a square meter. a square meter is 5x5 area. which means the plant must about 1.5 ounces per square foot.

4x4 area, 3 ounces per square foot
6x6 area, an ounce per square foot.

now clearly we both know that growing an ounce per square foot is pretty hard to do.
we preach that 100w per square foot is the measurement.. well if thats the case then we have to use a space less than 4x4. and then that means we must be able to get 3 ounces per square foot

and we both know getting 3 oz per sq foot in a 4x4 area is unreal.

thus.. getting 1 gram per watt is impossible pretty much... well you are able to grow 3 oz per square foot under a 1000w hps.. if you have a way of doing it.. then we all can grow 1 gram per wat.. you guys think its possible if we cram a bunch of clones in one spot with low humidity, we can get 3 oz per square foot?

any ideas about a plan to get 1 gram per watt consistently?

damn.. im high and doing this.. amazing. seems weed get my juices flowin.

anyone have any thoughts about this?

@find me:
quote: "a square meter is 5x5 area"
Actually, a square meter is 39.37" x 39.37" so, when you recalculate, it comes out to 35-oz (1000 grams) grown in 1 square meter (10.76 sq. feet) = 3.5 oz per sq. foot using a 1000w light.
Whether that is possible in such a small area, I have no idea.
Would be suh-wheet, but WAY out of my ability to make it happen.
I grow 4 plants at a time in a 48"x48" area and pull about 6 oz in total off of 48" tall plants (36" actual plant height without the 5-gallon pot of dirt under them) using a 600w HPS.
I know I have more to learn about proper growing (thank Jebus for RIU)...

DoobieBrother said:

@find me:
quote: "a square meter is 5x5 area"
Actually, a square meter is 39.37" x 39.37" so, when you recalculate, it comes out to about 1-oz per sq.ft. (and right about at the magical 1-g per watt using a 1000w light).

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hm? a square meter = 10.76 square feet. look it up on google.

but you are right, I made the mistake is saying 5x5 = a square foot.

10.76 square feet = 1 square meter so its a little more than 3x3 ( more like 3.3x3.3) which still means that if you had a 1000w light, in order to get 1 gram per watt, you would need to grow about 4 ounces per square foot within a 3x3 area.

Yeah, re-edited my previous post to correct myself on the 1-oz/sq.ft. gaff.

How do you think it is possible for people to get 1 gram per watt? growing 4 oz in a square foot under a 1000w hps just seems very hard to do. more specifically, growing 4 oz under 112watts of light is unrealisitc

Any idea on how it could be achieved?

HUGE op with all the extras. Lighting, co2, ventilation, temp control, nutes, etc. I've only seen 2 actual true 1g/watt harvests and they were both top of the line.

And awesome genetics.

DoobieBrother said:

And awesome genetics.

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PROBABLY one of the biggest factors. Great call!

DoobieBrother said:

(thank Jebus for RIU)...

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You said it. I have nicknamed my closet "Deathroom" instead of "Growroom." Made every conceivable mistake so far. w00t

Go vertical hydro with a light mover and 1 gram per watt will seem intermediate.

Also, weight per watt should be considered in addition to length of growth and countless other variables.

budlover13 said:

HUGE op with all the extras. Lighting, co2, ventilation, temp control, nutes, etc. I've only seen 2 actual true 1g/watt harvests and they were both top of the line.

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ah, I have seen one guy that got close to 1 gram a watt ( off about a few grams I think) and he wasn't using any co2 surprisingly not to mention he did a 12/12 from seed grow. The guy had 15 female plants under a 430w ( done within 12 weeks). he did a soil grow. perhaps if he did a hydro grow, he could easily smash that 1 gram a watt.

DoobieBrother said:

And awesome genetics.

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what kind of genetics we are talking about here? what kind of weed gives that much of a yield increase? big bud yields 600 grams per square meter.

If you want to calculate the cost-effectiveness of your grow I guess you'd use grams/KilowattHr. If you want to calculate how good your grow/yield was overall you'd need to incorporate weight, time, area used and wattage used in terms of actual measurable quantities (ignoring techniques used, bud quality etc.) The units would be something like... Grammes per (kilowatt-hour per square foot). People use grammes per watt cause it's easy I guess but in a lot of ways it's useless.

Birdyboy said:

If you want to calculate the cost-effectiveness of your grow I guess you'd use grams/KilowattHr. If you want to calculate how good your grow/yield was overall you'd need to incorporate weight, time, area used and wattage used in terms of actual measurable quantities (ignoring techniques used, bud quality etc.) The units would be something like... Grammes per (kilowatt-hour per square foot). People use grammes per watt cause it's easy I guess but in a lot of ways it's useless.

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I like your logic!

Birdyboy said:

If you want to calculate the cost-effectiveness of your grow I guess you'd use grams/KilowattHr. If you want to calculate how good your grow/yield was overall you'd need to incorporate weight, time, area used and wattage used in terms of actual measurable quantities (ignoring techniques used, bud quality etc.) The units would be something like... Grammes per (kilowatt-hour per square foot). People use grammes per watt cause it's easy I guess but in a lot of ways it's useless.

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Not to mention cost of nutrients, medium, and all other costs associated with type of grow used, etc., etc.. And cost of electricity (which can vary wildly around the world).
Yes, weight per watt is rather inaccurate.
It's all impossible to quantify, considering we all have different shades of green thumbs and can't all grow perfectly.
For my measly 6-oz I veg for 45 days (from seed in the soil) and flower for about 10 weeks. Was using Botanicare PureBlend Pro stuff, but am trying Jack's Classic & Blossom Booster this next grow to see what's up with it.
About the only real thing that can be said is "I used these, did this, and got this amount in "X" number of days at a total cost of "Y" money, so this is my cost per gram.", which would seem a more accurate measuring stick.

findme said:

hm? a square meter = 10.76 square feet. look it up on google.

but you are right, I made the mistake is saying 5x5 = a square foot.

10.76 square feet = 1 square meter so its a little more than 3x3 ( more like 3.3x3.3) which still means that if you had a 1000w light, in order to get 1 gram per watt, you would need to grow about 4 ounces per square foot within a 3x3 area.

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But a 1000 watt light is way overkill for a 3x3 space. That is 1000w/9 sq. ft = 111 watts per sq. ft. As I mentioned in my previous post, cannabis is good with a MAXIMUM of 55 watts per sq. ft of HID light. Therefore a 400 watt HID is perfect for a 3x3 foot space (9 square feet or roughly a square meter), which will provide 400w/9 sq. ft = 44.4 watts per sq. ft. Now if you get a gram per watt it is: 400 grams/9 sq. ft = 44.4 grams per sq. ft or 44.4/28 = 1.6 ounces per sq. ft, for a total of 14 ounces.

A 1000 watt HID over a more appropriate 5x5 area provides 40 watts per square foot. If you get a gram per watt, that is 40 grams per square foot or 1.4 ounces per square meter and a total of 35 ounces.