Maximum amount of light.

[kebnekajse]

How many lumens/sqft can a girl take without having to mess with additional co2, heat etc. I heard dif. oppinions on this subjet. Some say 5000, some 7000.

Reason I ask is because I have a closet with a 250w hps. Dimensions are 60x60 cm (2x2ft). I also have 2x70w hps that I don't use atm. I was thinking that I could use them in my closet, if there is a point to it. Pic shows how i would mount them. No reflector on the 70-watters, they would just hang.

This would mean that I have 2x5600+27000=38200 lumens/0.36m2=106111l/m2 (9530l/sqft). Is this overkill?

Take care

/k

 

[NYC_Diesel x Jack_Herer]

no it is not overkill. A sunny day outside is roughly 10,000 lumens per square foot. It comes down to heat. If you can easily remove the heat you can go as high as 10-12k lumens per square foot IMO. Your plants would love multiple light sources and light is always the most restrictive factor in growth and yield indoors. I say put them in if the heat isn't an issue.

 

[kebnekajse]

Thank you! I think I can manage the heat.

 

[NYC_Diesel x Jack_Herer]

no problem, remember that light power decreases by a factor of 4 every time you double the distance. So if you are getting 10,000 lumens per square foot from your light at a distance of one foot away, you are only getting 2,500 watts at 2 feet away. This is really important to remember with the smaller HPS lights such as 400 watt and below. I bet if you are growing conventional straight up plants your yields could be DOUBLES if you use LST or SCROG in your design to create a canopy that all three lights could rest right above.
Unless this closet has a lot of height to use, your diagram should work out well. But if you are growing straight up conventional plants to a height of more than 3 feet in that closet, it might make more sense to mount the smaller HPS light lower on the walls so that the lower branches of your plants can get light. But the best thing to do would be a SCROG in that size area in my opinion.

 

[kebnekajse]

I have not decided how my next grow will be yet. Probably lst since I don't like the thought of my girl being stuck in my cab... But what I would really like to do is grow one big tree. I can manage height wise, got just unde 2m to ceiling, but light penetration isn't very good with the 250w. So I would use my 2x70w in this scenario even if 5000L/sqft was the most light a plant could benefit from.

But since a scrog is flat, I thought the question was in place. Thanks for input, will try to use some extra light my next grow and see if I can spot a difference.

take care
/k

 

[NYC_Diesel x Jack_Herer]

A SCROG doesn't have to be flat, it can be vertical and would increase your canopy by up to a factor of 5! Using a flat scren with all lights resting above it, you have a 4 square foot canopy in a 2x2 area.
But, picture your plants growing in your medium in your closet. Then about 24 inches above the plant base you have your first 70 watter, then your second 70 watter about 18 inches above that, then your 250 about 24 inches above that. Then you set your SCROG screens (easy to find at hoome depot, chicken wire or other screen roughly 2x2 to 2x3 holes) running vertically up each of the 3 walls of the closet, starting 12 inches above the plant base, 2-3 inches from the wall, and extending 4-5 feet up each wall. This gives you a plant canopy of roughly TWENTY FEET!

Picture a light bulb above a plant. Even with a reflector right above it, the light is havign to travel further by going up and hitting the reflector and coming back down. The extra distance and process of reflection take away from the strength of the light. Plus, you can only get so much plant material close to the bulb directly underneath it. Now picture a bulb suspended with plants growing AROUND it. You triple the lighted plant matter being lit be each bulb (not quadruple since you are only using three walls).

 

[BuddyLuv]

I have over 7000 lumens per square foot in room, with no ill effects