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.
Roughrider Reviewed by Roughrider on . 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