1000w CFL > 1000w HID lumens per ft

Been interested in constructing a large scale CFL/T5 grow for a while but everyone keeps convincing me its a joke. Finally was brought to see a 10lb T5 room and now I want to make my own but better.

What I saw were several 4x6 ebb tables with fairly standard t5 banks above. Plants were scrogged.

I was thinking that although floros don't penetrate well you could toss out the scrog and in-bed the lights all the way from floor to the tops. I'm interested in putting 16 4' T5HO bulbs a foot apart standing vertically on end with a weak bank on top.

These 4' tubes are rated at 4500 average lumens and pull 54w. Here is a drawing I composed to calculate lumens per sq ft assuming the tubes put off 1k lumens per foot.

Birds eye view:


Lumens were derived with the following formulas and do not take into account reflected light:
1000+3(1000/4)+4(1000/9)+5(1000/12)+2(1000/25)
3000+5(1000/4)+5(1000/9)+3(1000/12)
4000+4(1000/4)+5(1000/9)+3(1000/12)
5000+4(1000/4)+6(1000/9)+1(1000/12)

So according to this I could provide most all of the plants with 5000+ lumens per sq ft from ground to top (many more than 5k at the canopy where the horizontal tubes would be).

According to Hortilux's site their super blue top of the line bulb puts out 110,000 initially which is 6875 lumens at the canopy and <3000 lumens towards the bottoms of the plants (not that it can penetrate the canopy if there are leaves in the way)

The vertical tubes pull 864w + 216w for 4 tubes up top to put the entire canopy at ~ 6800-8000 lumens per sq ft - (4500x4)/16 + vertical bulb lumens

Am I doing my math wrong?

**The lumen figures can be interchanged with lux (let me know if you need clarification on the difference)

Lumens don't matter as much as LUX

cfln said:

Lumens don't matter as much as LUX

Click to expand...

If you will notice this is MUCH higher lux than HID if considering vegetation blocking a single directional light source. Those lumen figures can be used interchangeably as lux figures as well (lumens per sq ft or per sq meter). The tubes run the entire length of the plant which maintains lumen density (lux) throughout the area for all 4 feet of height.

In other words the lux below and above canopy level are greatly different with HIDs but the lux levels are constant below and above and within the canopy with the fluoros.

Downloaded DIALux to compose a more accurate calculation on this but am having a hard time finding a lightsource profile the same as free standing fluoro tubes (they all have at least a small backing for the ballast whereas I would mount ballasts above or below).

Calcs show an average of ~4200lux at 2.5 ft with plants in the way. Pretty impressive considering many aim for 6k at just the canopy. 32000 max at the hot spots - need to work on that.