Led - watt per square foot?

  • Thread starter Ph 007
  • Start date
  • Tagged users None
Aqua Man

Aqua Man

26,480
638
New Gavita looks interesting. 345W consumption. Bar style 1100x1100 to be mounted at ~ 200mm. It's surely aimed at the 1.2 giving about 20w of LED per foot.
SPYDR do a comparable light, but feel to reach a good DLI, you need to do auto's as 12 hours light isn't enough.

Perhaps 20w is still for plants in veg. Though it's going to be strong growth.

40 in bloom gives me upper wilt, unless supported with co2. That's well spread lighting, hung around 350mm
Depends on the light efficiency.

Leaving out the corrections and just roughly compensating.

Without co2 max will be about 900ppfd (like that's pushing pretty hard in flower 12/12)

So you want a light that can reach that.

Say scorpion Diablo 2.9 ppf/w at 650w

2.9x650=1885 ppf (m2 is how that's measured so about 10.75 sqft)

So we take our goal of 900ppfd and divide my 10.75 = about 80ppf per sq ft.

So now that particular fixture is putting out 1885 ppf and we divide by the 80ppf per sq ft we want.

1885 ÷ 80 is about 24 sq feet. So a 5x5 perfectly without co2.

Now take a cheapo LED and maybe it's 2.1 ppf/w and equal wattage of 650w

2.0 x 650 = 1300

Now we want 80ppf per sq ft again so

1300 ÷ 80 = roughly 16 sq ft so you now only can properly flower a 4x4 with the same wattage.

This is why efficiency is so important and why some experience different watts per sq ft needs.

The first is 27w per sq ft.

The second is 40w sq ft.

Now these number are pushing a plant very hard without co2 and most won't be running those numbers but it's a safe bet when buying that you will have more than enough light to properly flower.

The exception is when you add co2.

Understand this was just a blab shirt version without compensating for light bleed, true ppf etc. But you don't need to be much closer than a roughly guide when buying as long as your reaching 700-900ppfd you have plenty of light imo.

Edited for math.... ran out of crayons 😁 that KS for the heads up @growsince79
 
Last edited:
growsince79

growsince79

9,065
313
New Gavita looks interesting. 345W consumption. Bar style 1100x1100 to be mounted at ~ 200mm. It's surely aimed at the 1.2 giving about 20w of LED per foot.
SPYDR do a comparable light, but feel to reach a good DLI, you need to do auto's as 12 hours light isn't enough.

Perhaps 20w is still for plants in veg. Though it's going to be strong growth.

40 in bloom gives me upper wilt, unless supported with co2. That's well spread lighting, hung around 350mm
I saw the ad and don't believe it. 345w for a 5 x 5. A properly lit 5 x 5 can easily produce 50oz without co2. 1400g/345 = 4.06gpw lol I call bullshit.. Good light for a 3 x 3 can make 500g
 
Last edited:
growsince79

growsince79

9,065
313
Sshz wasnt even getting that in his 4x4 with the 600w gavita and his was pretty much dialed in and pretty impressive to say the least
So many new lights on the market, and almost all of them exaggerate / lie in the ads. Best to check independent reviews and lab tests.
 
Aqua Man

Aqua Man

26,480
638
Is it the SPYDR saying 5x5 ? That would explain why they said 12 hours wouldn't reach a good DLI.

sshz doesn't have a 4x4 (or two) his space is 1.8 meters not 1.44 which gives him about 32w a foot growing 2.8oz in 10 weeks of bloom. 2.5gpw almost. That was his 108oz grow.
In metric, that's 350w a meter. The new gavita is the same sort of efficiency, being in the 2.7 region. However 240w a meter(based on a 1.2 tent), mounted 6-12" high. sshz was just over 20" usually. If he's our measurement stick :)
You happen to know how thier test was done? I would assume sphere?

I have no doubt if shhzz hit the bottle hard and made some tweaks he would be hitting 3gpw. A couple guys here are but yeah co2 in RW and dumping massive in like it's going out style lol.
 
Madmax

Madmax

4,733
313
Is it the SPYDR saying 5x5 ? That would explain why they said 12 hours wouldn't reach a good DLI.

sshz doesn't have a 4x4 (or two) his space is 1.8 meters not 1.44 which gives him about 32w a foot growing 2.8oz in 10 weeks of bloom. 2.5gpw almost. That was his 108oz grow.
In metric, that's 350w a meter. The new gavita is the same sort of efficiency, being in the 2.7 region. However 240w a meter(based on a 1.2 tent), mounted 6-12" high. sshz was just over 20" usually. If he's our measurement stick :)
I talk to sshz quite regulary and his grow space what he uses is 2 4x4 with standing room in the middle..i did have a pic of him measuring the room with plants in there but cannot seem to find it.i dont know where you get 1.8mtrs from ...its 1.2 x1.2 ..ea light is above a 4x4 space with 2ft in the middle for walking area..heres a pic of the room whats in his orange gasm thread..
Screenshot 20211121 125658
Screenshot 20211121 125604
 

Latest posts

Top Bottom