62 w/sft LED lighting too much?

hydro91

hydro91

Well-Known Member
Dear 420 forums,

Prior to my first grow with LED's I've decided to change up my lighting solution. I have a 5x5 tent and was hoping on fitting 4x Mars II 900 LED's to it.

I'm being told by the LED supplier that this is a little too much lighting for my tent and the 4 plants that'll be going inside the it. Does 62w seem a little over the top even if I were to be running CO2 canisters?

From the research I've done today seems I can get away with 62 w/sft although I'll need to be running CO2 canisters during the grow which I don't have a problem with. Is anyone able to possibly confirm my claims and research regarding CO2 canisters?

Thanks in advance!
 
4 mars 900s could grow 30 plants no problem. Those are 365 watt lamps, each one could feasibly flower 7-8 plants (In fairly tight groups). With co2 that's just a cherry on top. What's your nutrient plan?
 
I haven't decided on a nutrient plan yet but I'll be going organic soil as a growing medium. I need to source some of the nutrients here locally and see if they're even available but I'm sure I can find them.

Thanks for answering those questions too, I honestly didn't think 1 could flower 7-8 plants but that's great news it means I can start the grow sooner than later.
 
Hello , 4 -900 watt leds is over kill even with co2 , 3 is more than enough and 2 is plenty if you have good air flow to remove the heat as you can get a 900 watt about 14 inches from the plants with good penetration , I use 1- 900 watt mars 2 led and a 600 watt h.i.d in a 4x4x8 tent and works great .depends also on how many plants you intend on growing in the 5x5 space .
 
FelipeBlu said:
Unless you have cheap/free electricity, any combination of lights that provides over about 1400 average PPFD (over 12 hrs, for a DLI of about 60), is probably not productive enough per watt to be worth the extra cost.
:passitleft:
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Thanks for the information felipeblu and everyone.

This is better news for me then because it just means I can start with the grow sooner than later. :yummy:
 
Sorry to be the buzzkill...

You need 4x MarsII 1600 to fully saturate a 5x5 with enough light to optimally flower cannabis.

They always try to make newbies think they don't need a lot of light, but they're trying to make a sale, which they won't if they tell you to save up for something that's good enough for the area you want to light up

You can't go by wattage with LEDs because the difference between lights is huge.

To actually get something out of adding CO2 you need even more light, and temps of +30C in a closed environment with fully automated CO2/climate control.




Try looking into alternative lighting options, at the same wattage as MarsII lights, Quantum Boards will yield with 50% more ;)
 
hydro91 said:
Dear 420 forums,

Prior to my first grow with LED's I've decided to change up my lighting solution. I have a 5x5 tent and was hoping on fitting 4x Mars II 900 LED's to it.

I'm being told by the LED supplier that this is a little too much lighting for my tent and the 4 plants that'll be going inside the it. Does 62w seem a little over the top even if I were to be running CO2 canisters?

From the research I've done today seems I can get away with 62 w/sft although I'll need to be running CO2 canisters during the grow which I don't have a problem with. Is anyone able to possibly confirm my claims and research regarding CO2 canisters?

Thanks in advance!
Click to expand...
4 900W LEDs... ill have to follow this. have you confirmed that the LED' you're purchasing is genuinely rated at the wattage it claims to achieve?
 
They're not 900w from the wall I don't believe here's a link to the exact light I'm buying.

Mars II 900

They're rated at 364w from what I can see.

I think a better setup for my 5x5 tent would be as the LED manufacturer suggested.

4x Mars II 400's and 1x Mars II 900 in the middle.
 
PurpleGunRack said:
Sorry to be the buzzkill...

You need 4x MarsII 1600 to fully saturate a 5x5 with enough light to optimally flower cannabis.

They always try to make newbies think they don't need a lot of light, but they're trying to make a sale, which they won't if they tell you to save up for something that's good enough for the area you want to light up

You can't go by wattage with LEDs because the difference between lights is huge.

To actually get something out of adding CO2 you need even more light, and temps of +30C in a closed environment with fully automated CO2/climate control.




Try looking into alternative lighting options, at the same wattage as MarsII lights, Quantum Boards will yield with 50% more ;)
Click to expand...

Very interesting, Now I'm honestly so confused because I have some people saying it's too much and others saying it's fine.

Are 4 mars II 900's too much, just perfect or not enough?
 
hydro91 said:
Very interesting, Now I'm honestly so confused because I have some people saying it's too much and others saying it's fine.
Click to expand...

Yep, because most people don't actually grow with optimal lighting and others just qoute the sellers or sponsored content, good intentions, but not all too accurate :)
Most things will work and grow some decent bud, but there will be a very big difference in yield and cannabinoid/terpene output.




1547872951835.png





hydro91 said:
Are 4 mars II 900's too much, just perfect or not enough?
Click to expand...


Not enough!

You want +800 PPFD on every square inch of surface area and as you can see on the PPFD chart for the 900 @ 18'' it's not enough, now you could drop it to 12'' and increase the intensity, but this will decrease the spread.
This lamp covers around 1,5' x 1,5' if it is to be used to optimally flower cannabis.

It'll work, but 1000w HPS would be much cheaper, silent, reliable etc. and high efficiency COBs or QBs/strips are just better in every way ;)

1547873159879.png
 
I apologise for my ignorance but can you please explain what the numbers represent on the Mars II 900 chart you linked?

Do those numbers represent ppfd and do each of those square borders represent 6.6 inches in distance apart from each other?
 
If you average the PPFD readings in each box, you get the average PPFD for the indicated area. For example, the average PPFD for the 6” x 6” square directly below the center of the light is about 692. The average PPFD for a 30” square is about 425.

Contrast that with the minimum average PPFD of 925 needed to achieve a DLI of only 40 in 12 hours of flowering.
:passitleft:
 
FelipeBlu said:
If you average the PPFD readings in each box, you get the average PPFD for the indicated area. For example, the average PPFD for the 6” x 6” square directly below the center of the light is about 692. The average PPFD for a 30” square is about 425.

Contrast that with the minimum average PPFD of 925 needed to achieve a DLI of only 40 in 12 hours of flowering.
:passitleft:
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That was actually going to be my next question thanks for answering, How did PurpleGunRack figure out the optimal coverage was 1.5x1.5...

I know he calculated the average PPFD which I understand how to do but how can I convert any of those numbers into coverage area (for example 1.5x1.5)

I might be wrong when I assume this but is the green square 1.5x1.5?

That's the only thing I can't figure out.
 
Yes, the green is 18” square. If you add up the green boxes and the red boxes, and divide by 12, you get an average PPFD of around 530. This only provides a DLI of about 23 for 12 hours. Not sufficient for good bud.
 
hydro91 said:
That was actually going to be my next question thanks for answering, How did PurpleGunRack figure out the optimal coverage was 1.5x1.5...
Click to expand...



I don't calculate average PPFD, if you have 1500 micromoles just under the lamp and 200 in the corners, plants in the corners won't even get a third of the average anyway.

I just say minimum 800 micromoles EVERYWHERE in the growspace :)
You also have to take the height of plants into consideration, if you grow tall trees 800 micromoles is not nearly enough to keep the intensity high enough as you move away from the light and lower buds will suffer.

The 1,5' x 1,5' coverage for the Mars II 900 is based on the assumption that dropping it to 12'' above canopy will give you high enough numbers, might be stretching it, but it gives a more honest picture of what you can expect from it.
Now, it will grow decent bud in a 2x2 - 3x3 tent, but so will a 400w HPS at a fraction of the price.

When two or more lights are used the PPFD overlaps, so if the border between two lights is getting 400 micromoles from each light, you get 800 micromoles between the two lights.
 
The Mars II 1600 that PGR mentioned provides an average PPFD of about 912 over an 18” square at 18” height. This is much closer to ideal. But for a 5’x5’ tent, you would need at least 6 of them for adequate coverage. Not very efficient/cost effective.

This is why I like Autoflowering strains. You are not limited to 12 hours, so you can use lights that provide less PPFD, and still get a good DLI.
 
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