Too much light - is there such a thing?

I've seen the numbers for suggested light amounts per square foot of actual growing space, but I'm wondering if there is in fact a ceiling for this? So long as you can keep the plants temperate and not allow them to get burned, is their a ceiling beyond which the light can still hurt the plant or at the very least be of no benefit whatsoever?

I recently read an article by a fellow who claims to be using a 1000w HPS for a 3'x3' grow area, but can swing it because of the other measures he's taken to ensure proper climate control. Is this just totally unnecessary overkill, with little realistic ability of improving the crop over say, a 600w light for the same space? Or could this, and conceivably more wattage, really give whopping gains come harvest time?

That's a fantastic Q re: the ceiling after which there is no additional gain.
I can't give a specific answer but I CAN say that the best youcan hope for is to find what your limiting factor for growth would be, and work on improving it. It is USUALLY light for indoor growers. Once you have lots of light, you will want to look at other factors... soil moisture, atmospheric CO2, carbon availability in the medium, and of course your nutrient load. This is why many growers who use CO2 are not getting as much additional oomph from it as they could.

600w light is more efficient in lpw than a 1000. That's one thing to think about.

Your big thing is going to be temps when you really crank up the light.

Quote:

---

Originally Posted by sharer6969

I've seen the numbers for suggested light amounts per square foot of actual growing space, but I'm wondering if there is in fact a ceiling for this? So long as you can keep the plants temperate and not allow them to get burned, is their a ceiling beyond which the light can still hurt the plant or at the very least be of no benefit whatsoever?

I recently read an article by a fellow who claims to be using a 1000w HPS for a 3'x3' grow area, but can swing it because of the other measures he's taken to ensure proper climate control. Is this just totally unnecessary overkill, with little realistic ability of improving the crop over say, a 600w light for the same space? Or could this, and conceivably more wattage, really give whopping gains come harvest time?

---

i'm not sure if this helps...but i use multiple 1000's above 3x3 ebb & flow trays. its not the most effecient use of light/space. its just the way my room turned out and attempting to max out my space instead of maxing out the effeciency. if i had it exactly how i like-i would use 4x4 tables below 1000's. but if you can keep them cool 3x3 should be fine. you will probably have to keep your lights 24-30 in. away. i do deal w/ chrlorophyl bleaching from time to time because of the concentrated light-i usually have to keep them 18-24 in. away and my room never rises above 75. didn't mean to ramble-hope this helps.

there is a point at which you reach no significant gain if your not using co2 the general rule of atleast 50 watts minimum per sq ft or slightly more is adequete for decent results, if your using co2 it would be very hard to actually have to much light.
the 1000 watt light offers some advantage over the 600 when you consider the lumens output of each the 1000 is by far superior and when you factor in light intensity at different distances the larger light will always be the better choice, but depending on growing style a 600 could do equally as well in a 3 by 3 space.
the efficiency of the 600 shouldnt even really be considered as its not significant and the lumens per watt of the 600 and 1000 is very close.

Thanks for the input guys, I appreciate it. At this point, I'm trying to economize my plans, at least until I get my feet wet. So a lot of the questions I'm asking here are attempts to establish a kind of mental graph of "rules of diminishing gains" given the amount of space I have available, the amount of money I'm willing to spend, and the amount I'm hoping to grow. Those factors can wiggle a little bit, but not too much, depending on what I stand to gain, of course.

Given that the most elaborate I'm going to get C02 wise is one of those "microbe buckets" you see advertised in the magazines (or if I can find some kind of home-made alternative that works about as well or better), and I don't want to spend too much on air conditioning, fans, etc. 600w is probably going to be the most I'll invest in light wise, up front.

At the same time, I am willing to spend some coin on this - it's not like I'm looking to go totally "cheap and dirty". So, once again, it's within all of those qualifications that I'm looking to strike the best balance ("best" ultimately being judged on the criteria of yield quality, yield quantity, and how little of a headache the specific garden set-up causes me.)