The Ultimate Lighting Guide from DesertRat

so i've seen so many questions on proper amount of lighting for flowering that i have worked out the attached chart (version 2).

instructions for use
1. decide your target lumens per square ft - 3,000 if you want the minimum, 7,000 - 10,000 if you want the recommended amount, 10,000 + if you want to equal or exceed sunlight.
2. choose the correct row based on the size of your grow room
3. read across the row until you reach your target level of lumens
4. read up the column to see what kind of lighting to use.

note that the recommended levels of light for an hps lamp (16,25,36 square ft for 400, 600 and 1000 watts) actually gives you the minimum recommended amount of light. this chart helps you choose how much ore than the minimum you might want to go.

would appreciate feedback from experienced as well as noobie growers

I have one roblem with this chart, which is that under just about any decent hood (especially some of the nicer bigger ones, usually used for higher wattage hps) the area covered by the light is going to be easily twice the area that this chart suggests. At 1 ft. above the canopy you will be able to cover atleast a 9 sq ft area with any wide hood. They are assuming that the light is coming directly from the lamp at a 45 degree angle to some center point of the bulb, this is simply not the way that light actually disperses. It does however give you a good guide for how much light is lost at differing heights and gives a good picture of the real lumen difference between bulbs. Definately a chart worth a look, I just wonder how accurate the figures actually are if they are using their square footage to do the math for the lumens. Good find though, however you got it.
+rep

good points but i think i have them covered.

i did the chart myself and then checked the values for the 600 with my light meter. also was encouraged by the fact that the minimums from the calculations equal the recommended square footages of the lights.

i measured the angle on the three hoods i have access to and they were all close to 45 degrees. you're absolutely right, of course, that the coverage area will increase with the angle the light comes out. however, it does not change the chart except for the distances noted on the right side. in other words, lumens per square ft determine the grow area, not the distance from the light in this chart.

bump anyone