using power consuption of grow lights to know the area for each is a simple way to go yes, but simple dont mean it is bad. thats a simple, usefull and reliable way to give advices to growers. specially if you know well the product.
If you look at the original chart it was intended as a comparison of the different types of light used not as a absolute answer for how much light you need just a level playing field for all lights and each has their own range of wall watts. Then there are so many different aspects to take into consideration one main point is how much of the area is to be used just because you have thirty square feet if your only going to grow one plant do you need 1500 watts?
There are many successful growers here who with their styles have shown grows that even with mid thirty wpsf are readily done and they prove it with pictures and results showing they use the equipment that is recommended. Many of these growers have been here since the beginning and have well into the twenty Mars Hydro light range and have used other manufactures products but still come back so there must be something good going on here.
Then we get the people who show up tell everyone what they need and how to do it. That the lights are not right and they can grow a huge amount in a short time from seed and everyone needs the largest lights and max output but oddly we know that some of the cheaper smaller lights have been purchased but have yet to see a grow picture of even a sprout.
Personally telling someone just starting to go the max route is a quick way to failure there is a lot more to this than add light pick bud and it needs to be understood and developed at a sane rate I also believe many small lights are better than one large, I mean do I start seeds with a 1600 watt panel or use it to veg two plants?
I don't think so, myself aprox 25 wpsf sprout or clone, 30 - 35 wpsf veg to mid flower, 45 + wpsf mid flower to harvest (last 4 wks) this works best for me and gives a balance between power used, heat and output. During my last grow to establish a Mother plant for future grows from 4 strains the winner averaged 600 grams per plant and buds were near the same size, density,and resin development whether under a 900 watt Mars 2 or a 96 x 3 reflector and when the much criticized 60 x 5 was added they stretched to get under it and got larger.
The only real benefit I see with higher light output is finishing the plant it seems that with moderate light intensity some plants will just go on and on never really finishing which for a lot of people is not a bad thing resin color and effect takes awhile to understand
....
.....
