When peoplease say what is a led true watts, are you taliking about how many watts they draw at the wall? Can someone please explain
2 Likes
Yes that is it
Thanks for clearing that up. And they say to have 25 to 50 watts every square foot
1 Like
Someone else will surely point out that True Watts is not a good measure of an LED’s effectiveness or strength. I bought all of my LED’s based on a True Wattage I wanted to achieve (600) but PAR and umols (or something like that) are the real test of an LED lamp’s growing power.
I believe you can pick up a par meter and most companies tell you the par value at different distance but frankly, I don’t understand it all and have no meter.
50w/sq foot is the standard to shoot for I think 25 w would be kinda dull as far as the plants are concerned. I have 62w per sq foot currently.
2 Likes
So a 300w LED would likely be good for about 6 sqft? If so, how many plants are good in 6sqft?
I have three 300w LED’s and the true wattage of all three combined is 405 as the pull 135w from the wall. I have 10.5 square feet. I tested four different 300w LED’s and only the one I have pulled over 100 true watts.
If your 300w LED pulls 135 from the wall you would be looking at 22.5w per square foot and I think, your plants would want more light. They would grow but you would likely limit your potential. @Whodat66
If by chance we are talking about a top o the line LED and it actually pulls 300 true watts, yep you’d be fine.
2 Likes
Oh Hell no. $69.95 Mars Hydro full spectrum. I don’t want to buy another light, but I also don’t want to starve the ladies, so is this good for one, or maybe 2 plants?
Probably should point out that this is @Sirsmokes thread and not ours. That said, Mars are good lights and several people here I have seen grow with them. Not sure what they pull at the wall but likely it’s in the range of 130-40 true watts. Good light but that puts you on the low end of watts per sq foot needed to grow big buds.
Mine are Galaxyhydro’s 79.99 lol
2 Likes
Mine are 100 at wall I have 3 full spectrum dual cob
3 Likes
Nice @Sirsmokes I certainly want to enter the cob arena soon.
I also have 125w CFL’s X2 .
I am 28 days in flower today and my fingers are crossed hoping for a decent harvest of high quality herb.
1 Like
For some reason I can’t post pics. I’m saying are day 21 of flower but it depends on when you consider her to be in flower I’m counting day I switched to 12/12 but mine are puney compaired to what I see here. They were actu all started right in Midwest brown dirt with about a hr of good sunlight at 3 weeks after appeared they still had only 2 nodes so I brought them in grabbed some cheap 120w ge plant bulbs and nursed them the best I could. My wife went with it so I built a small room and she was cool with that so I pushed my luck with a led light and she was still cool so now I have a starter box with 100 cfl x3 6500k for clones and seed starts and a flowet box with 3 led and a exhaust fan aND filter on the way. Now she’s !@#$ed lol she let me take it this far so now I’m going over board planning for new lights soon more watts still led carbon charcoal filters everything. Started out with $100 budget now I probably have 700 in everything and still spending lol
3 Likes
I hear ya @Sirsmokes My budget was blown early on and now, we don’t talk about that hahaha
It’s like an addiction but once you start seeing the results, all worth it.
Oh yea I’ve talked to her she writes it off as a hobby I enjoy that’s an investment at the start but worth not spending 280 a month on meds
2 Likes
Plus it keeps me at home so there is that
1 Like
@Sirsmokes im about to complete a grow at 29watts per sq foot, and i can tell you the yeild isnt going to be great.
my current set up was 8 25w cfl bulps, my second flower tent ive just set up has againg 8 25w cfl plus an LED light that has a true 120w draw, this will give me 48w/sqf
so fingers crossed. id advise you to add some cfls. you want under 3000k clfs for flower. and over 6000k bulbs for veg.
hope this helps.
3 Likes
@Sirsmokes
I’m right there with you my friend! Started with a 300 dollar investment and quickly doubled that. Thankfully she’s not too salty about it as I’ve used my “walking around money” so it’s not coming out of the household budget but I still get the sigh and the head shake when the Amazon box arrives. It keeps us off the streets though! lol
1 Like
Right now I’ve got 50 per sq five got 100 watts on each plant
@SilentHippie she’s gonna shit when I order me a 400w mh hps bit I’m just going to write it off as winters comming garage is going to get cold so I will need that type of heat to keep my grown box warm… lol she will just roll with it
2 Likes
@Sirsmokes
That sounds like a perfectly valid reason to me. Make it sound like something you need (sounds like you might) as opposed to something you want. Lol 
As you guys have touched on, the 30-50 watts per square foot is good number. But it’s also kind of a dated number. Ppfd, par,umols, and such are numbers you should be more interested in when comparing lights.
However you definitely want to account for true wattage over model wattage or equivalent wattage. In the led world, lots of manufacturers like to say “300w” or “100 3 watt diodes” when in reality those are at maximum drive current, and the diodes are only ran at about 20-50% of max current. Even more so, one manufacturers 500w light has about the same output of another manufacturers 1200w light.
A lot of the new led tech is putting out almost twice the light as led’s from a few years ago. So it’s very difficult to say you need any specific number of watts. If you can get par data, you’re looking to stay around 1000 ųmols or less. Getting much over that will start to require additional co2 to be put to use. Over a given area, it’s entirely possible 30-40 watts of one light to get you there, and 50 watts of another light to produce the same amount of par.
Long story short, saying you need x amount of watts isn’t as useful as it once was. It’s much easier to say you need x amount of this specific kind of light. It’s the reason one 300w light cost $70 and another 300 watt light costs $600. They’re definitely not playing on the same field!
3 Likes