Hi GC!! I have a cab that is 3.5ftx2ftx6.5ft for my flower room, I need to know if 139w per sq ft is to much, it comes to 16,825 lumens per sq ft. If I am controlling the temp, will this be ok? I plan on flowering 4 clones. Any advise would be helpful,, thanx in advance!! Peace!!
i will be using 2 400w hps, im just wondering if there is such a thing as to much light, any advise is helpful,, thanx lay low for ur reply
There is such thing as too much light, yes, but I don't think you have reached too much. It's a lot, but if you can cool it properly the plants will make use of all that light. I know a guy who uses dual 600s in a 4x2 area. That might be a little overkill, but 2 400s would be about perfect imo.
1x 400 or 1x 600 would be more then enough. No point in putting 2x400 (800w) for 4 plants unless ur gonna let them get wild like growth. Most people say 100w per plant (where that came from i have no idea).... Control ur plants and use 1x400. If you was doing 6-12 then I would say yes on the 2x400 but just for 4 2x400 is a bit overkill imo. 5000-7000 lumens per sq foot is what the Cana Bible says u need. Personally I wouldnt use anymore then that. People on this forum will almost always say you need more then you actually do. Yes the more light the better but its kinda wasted after a specific point. Thats just 12.5 years of growing experience talking so each to their own. If you wanna pay the money for the light then do it but I think 1 will be enough.
thanx stoney for the advice! @ lay low that is my same grow space dims..... also i have 2 exhaust fans rated at 320 m3/h both on dimmer switches to adjust just right, am still building as we speak, guess i will make final decision once i have tested it for a couple of days, will update in a few days, thanx for ur advice!!
@ lay low, what are is results using that much light, fatter buds, bigger yeilds? how many plants does he put in that space?
To control the heat from 2 - 400s you need to have them in air cooled hoods attached to a strong inline fan at the terminus. I don't know what cubic m translates to in ft, but I'd use an inline fan rated at 400+ CFM in that situation. That guy runs different plant numbers every time. The last one he did 18 in a SoG grow. Before that I think he ran 4 in a more normal fashion. Plant numbers don't matter though. Whatever space you have, you should fill the entire area with an even canopy of buds. That can be accomplished with any number of plants. It just depends on the style of growing. More light = fatter, denser, heavier buds. 10,000 lm/ft² is the goal for optimal results. I don't know what StoneyAce is talking about, but in Jorge Cervantes Grower's Bible he recommends that much, and so does pretty much everyone else. It is a fact that plants will increase growth in a linear fashion all the way up to 10,000 lm/ft². That is full sunlight so it makes sense. Plants evolved to take full advantage of the sun's intensity. 2 - 400s would probably average a little under that number in real world use. Plus lamps lose brightness over a relatively short period of time so it's better to get more than you think you need. Serious growers replace their bulbs about once a year, sometimes after every single grow, because of the lumens that are lost as bulbs age. You will be very happy with the results from 2 - 400s. Just be sure to fill that canopy with some kind of training. Look at the plant training forum for ideas on how to do that. I have one plant right now that could fill that entire area by itself.
LayLow my info comes from years on top of years on top of years of experience. I am involved in a specific circle. I know alot of the people who grow up north. Inside and out. I am not just trying to blow smoke up someone's ass. No way in hell you need 800w for 4 plants. Plain and simple. Like I said above each to their own. If you wanna waste the power feel free. Its your money not mine. If you would like to read it feel free.... www.scribd.com/doc/13387/The-Cannabis-Grow-Bible http://www.scribd.com/doc/2522847/Marijuana-Cultivation-Bible http://www.marijuanaseedbanks.com/marijuana_lights.html http://www.lycaeum.org/~sky/data/mjgrowers.html More opinions... http://www.marijuanapassion.com/forum/archive/index.php/t-35481.html http://www.marijuanagrowing.eu/lumens-per-square-foot-t31567.html http://www.growmedical420.com/chaos/how-many-lumens-or-watts-per-square-foot-of-light-do-i-need/ http://boards.cannabis.com/growroom-setup/80167-4x7-5x8-room-1000w-overkill.html http://kingcannabis.com/growingC.html You asked for wattage per square foot....... Also notice what Bongulator says here...... http://www.rollitup.org/indoor-growing/122052-watts-per-square-foot.html I can sit here and link all day. If you need more links let me know. Not one of the links I have ready or books I have read say anything about needing 10,000 lumens/sq foot. Its just pointless. 7500 or more... The more dosnt mean 10,000lumens. Besides it hasnt been proven that 10,000 per sq foot does any better then 5k or 7k. You might need all that wattage if you let your plants get out of control and have them grow like they would in the wild. If your growing plants 3-4 feet or under you dont need anywhere near 800w to pull a nice harvest. If you let them get wild looking and out of control you might need the 800w just to penetrate the plant. Like I said grow it right and you will never need that much. Ghunter pulls 2-3oz per plant in a frige under 290w of light using a SCROG. I have seen people let their plants go and have 5 foot plants under 600 or more watts pulling under what Ghunter is pulling. Lights are not always the most important thing in a grow. I would focus more on the plants and less on the light above them. Not trying to be an ass here just trying to help someone grow as efficient as possiable. If you wanna use the "more light is better" motto then throw 2x1000w in there and be done with it.
Marijuana Cultivation Bible 3 How Much Light Do I Need? Technology has advanced so much in the last 15 years that we are constantly refining the process and updating what we know works best for growing. Current theory holds that the minimum amount of lighting needed to sustain growth is around 2,000 lumens per square foot. Mid range is around 5,000 lumens per square foot. Optimal is 7,000 to 7,500 or higher lumens per square foot. How Many Watts Do I Need? The general rule of thumb for providing light for an area is a minimum of 30 W per square foot. 50 W per square foot is optimal. You can determine the proper lighting for your area by using this formula: Watts x Square Feet For example, say you have an area of 10 square feet and a 30 W. That would mean you have a 300 W per square feet minimum. Also, remember that fluorescent's are weaker and emit less light than an HID. This means you will need 5 times the amount of wattage to equal the output of an HID. So, 30 W of HID would equal 150 W of fluorescent's. This is why it is advised to provide a minimum of 30 W per square foot for HID lights and a minimum of 150 W per square foot for fluorescent's. This is all important because the light intensity will directly affect the quality and yield of your crop. If you have less than optimal lighting your yield and potency will be reduced and buds will not develop as dense. This point can not be stressed enough. You must have the right amount of light for your space to grow high quality bud. Can I Have Too Much Light? The basic answer is no. According to the law of diminishing returns, you could theoretically reach a point when your plants just couldn't absorb any more light, but it would be impossible to have that many lights in your space. Heat from the lights would become a problem long before you ever reached that point. So use as many lights as you want, just control the heat. i was reading the links you put up stoney, and i can see what ur saying, but then the book contradicts itself kinda, by sayin that u cant have to much light, i guess really it comes down to if i wanna pay for it and can i control the heat,, if i use only 1 -400w hps it lowers my wpsf to 63, and my lumens to 7,600 psf i dont know i guess i will see what happens, i can always take one out or add one as i need
I don't care how many opinions you link. Whatever he can yield from a single 400, he will yield much more from 2 400s. I don't care about efficiency. I care about producing the biggest most dense buds possible, and that takes a lot of light. Also I'll take Jorge Cervantes opinion on lighting over 1000 random websites and random forum members opinions.
Like I said... Each to their own. I know what I know from years of experience and from people who have over $100,000 harvests. There is a point when your are in a way wasting electricity. Like I said if you wanna look at it like you cant have too much light then throw 10x1,000w fixtures for the 4 plants. You have to draw the line somewhere or it will never end. most everyone will tell you its in the 5,000 lumens/sq root range. Some do push it to 7k but I havent had any of the people I know come back braggin how much more they got when they did 7k/sq foot. What if we do 50,000w over 1 plant 0.0 Again this isnt a pissing contest for me. I am just trying to give the best advice I can. If electricity isnt a factor for you then do the 50,000w and LMK when happens. "Know when to say WHEN!"
uber kill IMHO. Lights are certainly important, but i have to agree with stoney that experience and personal technique go a long way. its not all about the light, lots of other things to control that if not done properly, not even a private sun will overcome. If money is no issue, why not trying a simultaneous grow, one using 1 400 hps and another using 2. Same seeds, same nutes, same everything. Share results.... We should start thinking about a way to capture data from the fellow growers to actually have harder data to go to. Interesting thread. Peace
I'm sure you mean well, but there's a lot you don't know about lighting it seems. I don't care how many years you have been growing or how many growers you hang out with. That means absolutely nothing. For every link you posted I can post 2 more that agree with me, but that is pointless and unnecessary since you already linked proof of my stance. Let's say 7500 lm/ft² is optimal. This is from your own link. Now the fundamental flaw in your entire argument is that you assume that taking the lumen output of the bulbs and dividing that by the square footage of the grow area gives you an accurate measurement of the actual lumens that hit the plants. That is not even close to being accurate. Light intensity diminishes in inverse proportion to the square of the distance. In more basic words, light intensity falls off dramatically the further away from the bulb. A 100,000 lumen light source at 2 feet away only produces 25,000 lumens, and at 3 feet away 11,111 lumens. Let's say this 100,000 lumen light source is in a 3x3 grow tent, now I'm sure you would say this is way too much light. OMG that's over 10,000 lm/ft²! In practice you will not come anywhere close to that number at the plant canopy. If you had that light 2 feet above the plants (which is reasonable), it would only produce 25,000 lumens, giving 2777 lm/ft². Doesn't sound like too much now does it? And that is pure theory. In reality you would not even get that much since reflectors are not perfect. You can easily subtract 10% from that number due to reflector inefficiency to arrive at a more accurate representation. So now we are left with only 2500 lm/ft². Not even close to the optimal target! I've seen a 600 watt HPS measured only 1 foot away and not even reach 7,000 lm/ft². That is an actual measurement taken with a light meter. That is a 600, which produces way more lumens than 400s do because of both more watts and higher efficiency. If a 600 can't produce the optimal amount from 1 foot away, 2 - 400s definitely won't go above that either in the OP's setup since he will likely have them even further than 12 inches so that they spread light better. For every single inch the bulb is further away light intensity falls off dramatically as has already been shown. Now do you see why that book that you linked says that you basically can't fit enough lights into an area to ever go beyond what the plants can use? This is all just for the very top of the plants, the canopy. When you get 1 foot down into the canopy they will now be getting way way under optimal lighting, and 2 feet would be a joke as to how little lighting those buds would be exposed to. Ideally you would want to be over the optimal number at the top so that lower buds can get decent lighting as well. What does that all mean? 2 - 400s would stomp all over a single 400 in his grow area, and they would STILL not reach your own optimal number of 7500 lm/ft². Growth would increase in direct proportion to his increase in light intensity. There would be no wasted lumens at all. You are stuck in your own world dude. You think because you grow a certain way, that everyone should grow that way. It seems in all your experience you have shut yourself off to actually learning new and better ways of growing, either that or you simply have never understood the properties of light.
yes shug , i have done it b4 on my 1st grow, now i have upgraded to mh for the veg and hps for flower, but hps will work all the way through! peace!
Believe what you want. Lets see those links saying you need 10k lumens/sq foot. All I do is hang around people that grow. Thats basically all i ever see is plants no matter where I go. I know more about light and growing then you probabley know about yourself. Its all in experience. How much experience do you have. I have personally had over 60 harvests under my belt and seen probabley 200 more on top of that with my own 2 eyes (not looking them up online). I know my shit. I can care less how many watts you or the other guy runs. Run 50,000w for all i care. He has 4 plants. There is no need in having 800w over 4 plants plain and simple. I dont care if his grow room is 100x100. You do not need to fill the entire room with 10k lumens/ sq foot just for 4 plants. Its stupid and a waste of money. Your looking at it one way. Light, Light, Light. Lets do some numbers shal we. This is where I usually shut people up. 400w 400w 200w (6 in Vortex x2) 15w (Box fan inside the room) --------- 2015w Total Ok your using 1015w for your grow. You have 4 plants. Total Weight - 112g Total Watts - 1015w Total Grams per watt - .11 g/ watt Total Weight - 224g (2oz per plant) Total Watts - 1015w Total Grams per watt - .22 g/ watt Ok lets say you pull 1 lb which is 1/4 lb per plant Total Weight - 448g Total Wattage - 1015w Total Grams per watt - .44 g/ watt Now my way 400w 100w (Vortex fan) 15w (Bax Fan) I am using 515w. I have 4 plants. 400w 100w (Vortex) 15w (Box Fan) --------------------- 515w Total Total weight - 122g Total Watts - 515w Total grams per watt - .236 grams/watt (Already more grams/watt then you get pulling 2oz per plant)) Total weight - 168 (1.5oz per plant) Total Watts - 515w Total Grams per watt - .362 grams/watt Total Weight 224g (2oz per plant) Total Watts - 515w Total Grams per watt - .434 grams/watt Total Weight - 280 (2.5 per plant) Total Watts - 515w Total Grams per watt - .54 grams per watt All I have to do is harvest 2 oz or so per plant from my set up. To match me you have to harvest 1/4 or more per plant to even get close to the same gram/watt as I am getting. I am using 500w less power and still getting more grams/watt then with 2x400. Good luck matchin it. Just because you double the light dosnt mean you double the harvest. Me pulling 1.5-2.5oz per plant is still more efficient, and actually more doable then your 2x400 pulling over 1/4 lb per plant. From my experience your gonna need closer to 1,000w. Not 800w. Where are you "stompin all over it?" Looks to me like my .54g/watt is stompin all over your .44g/watt and your paying a higher electric bill. Math dosnt lie but hey I guess I dont know what I am talking about.