What is the ultimate lighting requirements for growing?

A customer has a question and I hope we can get some opinions on it, thanks.

I’ve been reading up on a lot of your material and I have a few questions: 1- what is the ultimate lighting requirements for growing? LED or a combo of MH & HPS - and what wattage would be best 400 or 600 W? 2- you don’t mention the distance between pot - what is the ideal spacing between pot so they don’t affect each other? Is if OK, if I ask you more questions, when some arise? Thank you for your help and reply DW

There are several threads and discussions covering these things, I would suggest that person join the group and do some searching. If not, they can always start a new thread and I’m sure several people would be willing to offer some info.

The easiest way to say what ideal lighting is by know your photosynthetic photon flux density. Generally measured in umols per second per meter squared. For flowering stage, the ideal ppfd is around 800 umols. You can get there by using any type of light. A lot of the budget fixtures won’t exactly give you the ppf of a light to figure it out. So you’ll see a number like 50 wall Watts per square foot used a lot. That number doesn’t account for very efficient leds, so it’s very possible to meet par requirements with less Watts. Those fixtures will cost quite a bit more per watt though.

For a mh/hps setup you’re looking for something like a 400 watt for 3x3, 600/1000 Watts for 4x4, and a double ended 1000 Watt for 5x5. As stated earlier, those are for ideal par levels.


What size Flux Capacitor do I need to achieve that?


Haha, the size of your space will generally require gigawatt requirement.


1.21 gigawatts


I did okay with just an HPS bulb. Not optimal, but okay. One step up would be to get a MH conversion bulb that works with the HPS ballast and use that during vegetation stage. LEDs can be more efficient than MH/HPS but not a huge amount. The important thing to watch when buying an LED lamp is the actual power draw from the wall. Not the marketing hype! You need 40-50 real watts of LEDs per square foot for good flowering. 50 watts per square foot for HPS.