Failed attempts at understanding lighting requirements

Hey guys,

Frequent lurker on the website, and officially decided to create an account today.

I'm hoping someone can help me make sense of lighting requirements for my growspace. I have browsed thread upon thread, watched video upon video and frequented a multitude of articles, and still feel as clueless as I did a few weeks back.

My grow tent is 1m x 1m x 2m (3.3 x 3.3 x 6.6). I bought a quantum board with Samsung lm301b diodes, actual output 220w, 2.7 umol/J, 600 umol/s.

I want to purchase a second identical quantum board to supplement the light in my growspace, I'm just not sure if it's necessary? This is my first grow, no co2 supplementation (obviously, given my level of noob). I have tried understanding PPFD, DLI, umols, lux and whatever other information I can find, but it's just resulted in information overload.

Can anyone shed some "light", haha?

220w is not enough for that area; a second light would be advisable.

You'll also gain some efficiency in the process since you won't need to run both at 100%

Keep reading

Thanks, @Billy the Mountain

I thought as much. My confusion came in when the grow shop I purchased the light from advised against purchasing an additional light, stating that it would be a fruitless purchase. I am not sure if growers this side of the world take on a simplistic approach, but three grow shops have advised that more than 220w/240w for a 1x1x2 is pointless.

It genuinely boils down to what light you're using, as to what height/what intensity for the plants.

Generally speaking, as it applies to LEDs without c02 supplementation, 35 watts per sq ft is solid for flower. Let's just round down & call yours 3x3, so 9 sq ft x 35 = 315. This doesn't mean your 220 watt light won't do well, you just might have to sacrifice some space around the walls due to lack of light spread and/or intensity. You mentioned getting a second fixture? --that oughtta do it, and you can dim or raise the fixture to compensate if it's too much.

Just my opinion, i just use "plant response" as my PAR meter; if the plants look good, the light stays. If they're seemingly stressed out or taco'ing, etc, i adjust accordingly. Also having used the same fixture for 18 months I kinda know where it needs to be.

livelikejay said:

actual output 220w

Click to expand...

another of those would be good. 440w is about 40 w/sq ft

livelikejay said:

Thanks, @Billy the Mountain

I thought as much. My confusion came in when the grow shop I purchased the light from advised against purchasing an additional light, stating that it would be a fruitless purchase. I am not sure if growers this side of the world take on a simplistic approach, but three grow shops have advised that more than 220w/240w for a 1x1x2 is pointless.

Click to expand...

Just rely on the grow shop's materials and products, and not always their advice. Most of them are giving outdated info IMO and you should always take what anyone says with a grain of salt. Even this comment, lol.

Thanks for the advice, everyone. I appreciate it.

I'm not sure if this is worth factoring in with the acquisition of an additional light, but should I be concerned about "ppfd hotspots (?)"? As in the ppfd coverage of each fixture overlapping to the detriment of the plants?

livelikejay said:

Thanks for the advice, everyone. I appreciate it.

I'm not sure if this is worth factoring in with the acquisition of an additional light, but should I be concerned about "ppfd hotspots (?)"? As in the ppfd coverage of each fixture overlapping to the detriment of the plants?

Click to expand...

No

You can get one of the phone light meter apps to help you position the lights if need be, they're fine for comparative measures.

Thanks for the insight. I'm sure this will be the first of many enquires on my end.

Cheers