How much light for Vegging and Mothers?

[McToker]

It seems that most of the info on how many lumens are needed pertain primarily to flowering. I guess I actually have two questions.

How many lumens per square foot are needed for vegging?

and

How many lumens per square foot are needed to maintain healthy mother plants?

I have a 250 watt MH lamp but heat is an issue in my grow room. I'd like to run flouros instead. I'm currently using 4 foot T-12's for my seedlings and could easily add more for vegging and or moms. The only figures I could find for the T-12's said they are 3050 lumens each. That figure seems too high to me. I wouldn't mind switching to T-5's, if needed, to get enough lumens for the job. The area is roughly 4' x 2' or 8 square feet. I have used CFL's in prior grows but, surprizingly, they generate quite a bit of heat.

Thanks,

McT

McToker Reviewed by McToker on 02-03-2010. How much light for Vegging and Mothers? It seems that most of the info on how many lumens are needed pertain primarily to flowering. I guess I actually have two questions. How many lumens per square foot are needed for vegging? and How many lumens per square foot are needed to maintain healthy mother plants? I have a 250 watt MH lamp but heat is an issue in my grow room. I'd like to run flouros instead. I'm currently using 4 foot T-12's for my seedlings and could easily add more for vegging and or moms. The only Rating: 5

[redtails]

In my experience, you don't want to give the moms too many lumens unless you plan on trimming a lot. I have a 200w cfl, 12,000 lumens, for a little mom & clones in a 4sq ft box and I could scale that down to probably half. I'd say 2000-4000 lumens per square foot should be a good range. The point is to keep the mom healthy and growing but not vigorously growing, & the clones/seedlings don't need too much light at first. I think you could use 4 or 5 of those t12's for the mom & kids, as long as your mother doesn't get too tall or you keep the canopy the only growing part.

[McToker]

Thanks redtails. I guess I'm set for moms and seedlings.:thumbsup:

The only issue remaining would be how much light for vegging. I'm hoping that I can use the same area for both vegging and keeping moms. Although, I suppose if I need more to veg I could add some 2-foot T-5's as side lighting at one end of the area. Just thinking out loud.

[Roughrider]

You need the same amount of light in terms of area...but you can use a lot less for vegging in terms of amount of light per plant. The reason is simple--plants are smaller during veg. Smaller plants = smaller space. In a 15" x 15" area, you can fit maybe one plant in flower. You can easily take four plants through 3 weeks of vegging in an area that big. So you need 8000 lumens to grow one flowering plant...but you can veg four plants with the same amount of light. Same amount of light for area...less light per pants, because the plants are smaller.

Fluoros are especially good for vegging because one of the major problems with this type of light--poor canopy penetration--isn't an issue when plants are less than 8-10" tall. I can't vouch for how you'll do with mothers and those lights, though...depends on their size.

[McToker]

Thanks Roughrider. That helps a lot. I was thinking that I could add some shorter tubes on the side of the moms to handle the lack of light penetration from above. I suppose I could also go back and re-read the threads on bonzai moms.