Lumens per square foot?

[DUTCH_MASTER]

Are lumens per square foot really important during veggin? I understand it is during flowering, but when veggin only to 12 inches do I really need to live by this? What's a cheap but effective light for veggin 10 plants?

 

[Locked]

Lumens are always important but you can get by with flouros and CFL's during veg...and then go to HPS for flower....

 

[DUTCH_MASTER]

Lumens are always important but you can get by with flouros and CFL's during veg...and then go to HPS for flower....

Thanx. Are U using CFL'S? If so how many will I need for 10 plants?

 

[Locked]

Thanx. Are U using CFL'S? If so how many will I need for 10 plants?

I only use cfl's for my seedlings now...then they go into the tent under Hid lighting...look up in member list Mentalpatient...he does some great grows with nothing but cfl's....

 

[DUTCH_MASTER]

I been getting great feed back. How can I thank members? My screen does not have the thank you tab any longer.

 

[Locked]

I been getting great feed back. How can I thank members? My screen does not have the thank you tab any longer.

They did away with the thanks button in order to make the site run faster...

 

[DUTCH_MASTER]

That sucks. But thank U Hamster.

 

[Locked]

That sucks. But thank U Hamster.

No problem...that's what we are all here for...keep it green

 

[The Hemp Goddess]

You might want to check out the T5 fluors. They are tube fluoros and are high output. They have a higher watt/lumen ratio than some of the lower wattage MH lights. The 54W tubes put out 5000 lumens and are available in 2' or 4' fixtures with 2-8 lights in each fixture. I used to use a 400W MH to veg, but discovered that my 216W T5 does just as good a job at half the energy usage and heat.

 

[mountain man]

Thanks Hemp Goddess ! Good tid bit on Veg lighting !

 

[DUTCH_MASTER]

You might want to check out the T5 fluors. They are tube fluoros and are high output. They have a higher watt/lumen ratio than some of the lower wattage MH lights. The 54W tubes put out 5000 lumens and are available in 2' or 4' fixtures with 2-8 lights in each fixture. I used to use a 400W MH to veg, but discovered that my 216W T5 does just as good a job at half the energy usage and heat.

Can a 4' four light T-5 fixture provide enough light for 10 or 16 veggin plants?

 

[ozzydiodude]

Yes, jusy try to fit all the plants under the lights or rotate them every day to get good light to all the plants.

 

[DUTCH_MASTER]

Yes, jusy try to fit all the plants under the lights or rotate them every day to get good light to all the plants.

Ozzy, thanx a million man. Where did U get Ur avatar? Its awesome.

 

[ozzydiodude]

I been trying to remember myself. it works for me I want to spread Green Mojo around the would. Have someGreen Mojo for your ladies.

 

[The Hemp Goddess]

Can a 4' four light T-5 fixture provide enough light for 10 or 16 veggin plants?

LOL--size is relative--how large a plants are you talking about, how large is your space? I have a 4' 4 tube T5 in a closet that is 4 x 2 x 4. I get thick lush growth, but think that if the space was any larger, I would add more light.

 

[DUTCH_MASTER]

LOL--size is relative--how large a plants are you talking about, how large is your space? I have a 4' 4 tube T5 in a closet that is 4 x 2 x 4. I get thick lush growth, but think that if the space was any larger, I would add more light.

The grow tent is 4x4x6.5.

 

[Rolling Thunder]

Are lumens per square foot really important during veggin? I understand it is during flowering, but when veggin only to 12 inches do I really need to live by this? What's a cheap but effective light for veggin 10 plants?

Yes, I believe you need to live by that rule, if maximum yields are what you're after. I guarantee you that those growers who are averaging 1.5 to 2.0 grams per watt, on a consistent basis, are not vegging under a different kind of light, at lower lumens/sq ft, than they flower under. For maximize yields, you need to get the little ladies into the fastest cycle of growth possible during the veg stage. That usually means giving them the same amount of lumens/sq ft, as soon as they're out of the gate, as they'll receive during the bloom cycle.

Now, once you have attained a maximum level of momentum in the veg cycle, you want to maintain that momentum going into the bloom cycle. However, that momentum can be easily broken or disrupted by changing changing the light and lumens/sq ft going into bloom. The change of light spectrum and greater lumens/sq ft is enough to stress the ladies and slow their growth; which means a loss of momentum during the transition from veg into bloom.

However, this advice is relative only to those indoor strains that receive a proper veg period. As you likely know, there are some indoor strains, like Neville's Haze for example, or some tropical pure sativas, that receive no veg period, that is, in terms of the 'veg' light cycle. But for those that do receive a proper veg light cycle, that first 12 inches of growth, and how fast they achieve that height, will have a big impact on their speed of growth during the bloom cycle. - RT

 

[StoneyBud]

Hey Dutch Master, there is an easy way to understand this.

It's NOT the size of the room that is a consideration.

It's the size of the PLANT CANOPY.

Plants grow as a result of Photosynthesis. There is a DIRECT relationship to the quantity of lumens striking the plant canopy and the amount of growth and what type of growth a plant will have.

You can use candles from 8 feet above your plants to veg with. You'll end up with skinny, long legged, unhealthy, wispy little half dead plants, but they'll grow some.

However, if you're looking for healthy, thick stemmed, short node, fast growing, thriving plants, you need to approximate what the Sun does in natural light.

The sun, at high noon on the equator, provides about 10,000 lumens per/square foot of surface.

It's not feasible to use 10K lumens in a grow room, because the costs would be astronomical, so 5,000 lumens per/square foot of PLANT CANOPY is an amount that most experienced growers accept as a standard to provide as good of growth as can be, inside.

When the plants are small, they have a much smaller "footprint". That is to say that the PLANT CANOPY is much smaller than it will be when the same plants are flowering.

If you have 12" plants or less, they can be placed closer together where the PLANT CANOPY is a much smaller area to light.

When this is done, it takes less light to make 5,000 lumens per/square foot of PLANT CANOPY than it will later when the plants take up much more area.

So, to make your plants grow at the best overall rate and with the best overall health, you should use 5,000 lumens per/square foot of PLANT CANOPY.

(I've emphasized PLANT CANOPY to make it clear to everyone that the room size IS NOT what you base your light levels on.)

 

[Rolling Thunder]

However, this advice is relative only to those indoor strains that receive a proper veg period. As you likely know, there are some indoor strains, like Neville's Haze for example, or some tropical pure sativas, that receive no veg period, that is, in terms of the 'veg' light cycle. But for those that do receive a proper veg light cycle, that first 12 inches of growth, and how fast they achieve that height, will have a big impact on their speed of growth during the bloom cycle.

Oppps! The above statement in not very clear. Not sure what I was thinking about, but the above advice, about vegging under the same light as you flower under applies to all indoor strains, regardless of whether (or not) they`ll receive a proper veg light cycle.

About the 5000 lumens per sq ft rule, I`m not sure where that came from. I`ve never heard of that before I ventured upon this website. Im one that believes you can do better indoors with far more lumens per square foot, especially if you`re growing a long flowering pure sativa, for example; or sativa dominant hybrids. I would regard 5000 lumens per sq ft as a bare minimum, and not an optimal range for maximum yields. - RT

 

[StoneyBud]

About the 5000 lumens per sq ft rule, I`m not sure where that came from. I`ve never heard of that before I ventured upon this website. Im one that believes you can do better indoors with far more lumens per square foot, especially if you`re growing a long flowering pure sativa, for example; or sativa dominant hybrids. I would regard 5000 lumens per sq ft as a bare minimum, and not an optimal range for maximum yields. - RT

The 5K lumens is the current cost effective amount. More than that, up to the 10K that you get from natural sunlight, is cost prohibitive.

Dealing with electrical costs, heat build-up, air movement and IR from the lamps make 5000 about as much as anyone would want to put on an inside crop.

It's the maximum you'd want, not the minimum.

More than that and you start running into lots of other problems.