Coverage area question

[NeilNM]

I've been unable to find an answer after searching the forum. It's about the advertised coverage of LED lights. For example "4'x4' for veg and 3'x3' for flower"

I understand that much more light is required during flowering to allow for light penetration to the lower buds, but is it always needed?

I intend to use a SCROG method which will have all the bud sites on a flat plane, so there is no need for the light to penetrate lower down, in fact all the lower growth will be removed.

My question is, in a 3x3 tent will a light with a 3'x3' area coverage for veg also be enough for the flower phase in a SCROG grow?

 

[Emilya Green]

no. The light needs in bloom are much higher than in veg. Will it work? Yes... but you asked if it is enough. You will get buds... they just wont be as hard and dense and as powerful as they could have been, with better light. The scrog and the tight canopy will help, but you can only milk so much out of those lights.

 

[Dwight Monk]

The reason the numbers are different is in Veg you are at a farther height from tops of plant (most people anyway ), as the light spreads out more when higher and less when closer to the plant (take a flashlight and hold it 10 inches above table and then 24 inches and see how much broader area the light covers). On top of the needs more/stronger light in Flower to work the best, but kinda what you doing by having light closer to the tops.

 

[TorturedSoul]

People recommend 50% more light-energy in the flowering phase than they do in the growth phase.

Traditional growth light schedule is 18 hours on / 6 hours off. Traditional flowering light schedule is 12 hours on / 12 hours off (which is a 50% reduction in the hours of light per day).

Hmm...

.

 

[Emilya Green]

Here is a chart that I made as I was figuring out the proper wattage and distance to run my 6x COB array. You can see from the colored sections of the chart, the recommended LUX for each stage of growth.

 

[TorturedSoul]

While any measurement of plant lighting that is based on the lumen is a poor one... Shouldn't the unit on the left of that chart be lumen? Lux already takes distance and spread into account - it's the amount of illuminance reaching the suface in question (in this case, the canopy). E.g., a 12,000-lumen light source in a room might be capable of providing 500 lux at the floor level. Either that or remove the distance lines, I suppose, and just plot lux in regards to plant size/age.

 

[Emilya Green]

This was direct measurement at the various distances, using my lux meter... so it is what it is. I could also do the conversion to PAR based on the CRI of my lights, but that would blow too many minds.

 

[Cornercat]

I've been unable to find an answer after searching the forum. It's about the advertised coverage of LED lights. For example "4'x4' for veg and 3'x3' for flower"

Besides needing more light for flower, the advertised coverages are all exaggerated by the LED companies to sell their products. When they say X' x X' for flower, they're stretching that out to the bare minimum levels that a plant will kindof flower at. Subtract -1' from every advertised coverage to get the real, quality veg/flower footprint. If you try to stretch beyond the already stretched coverages you'll be disappointed.

 

[Vegan4life]

Answer to question is NO. Rule of thumb I use is actual watts per square foot. 40 - 50 actual watts per square foot for flower, you need to know actual watts draw from the wall. 3' x 3' area should have approximately 360 - 450 watts from the wall for flower.

 

[NeilNM]

I understand, but when they say that it will veg a 4'x4' area, do you then move everything over to a 3'x3' area when you switch the lights? Seems crazy. Then many lights have one power setting for veg and another for flower and I know from observation that the light is brighter in the flowering mode. All very confusing.
Anyway, you have all helped me to decide between the Mars Hydro TS100 and the TSW 2000. Going to order a TSW2000. A little less output than Vegan4life recommends, but it's a compromise between potential yield, power consumption and heat build up.
Thanks for the input everyone.