So...when should I wip out the ol' 600?

one11 said:

I've got a few seedlings coming along. I've been giving them a mix of 18 hrs of direct sunlight, and 1 cfl. But they're growth seems to have slown down. I dont have anymore cfls, just a 600watt hps. They only have those 2 little rounded leaves and two little spiky leaves in the middle. Is it okay to put em under the big boy now?

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bobbyhopefeild said:

at seedling stage , from 1 week to 5 they only require 4000 lux , which is about a 5ft 58w T8 striplight, when they are in vegetative growth they require about 27000 lux and in both stages they need far more blue light around 6500 kalvin, in flowring they need 100000 lux and require far more red light, the spectrum of light that HPS provides and less blue light
now, i certainly wouldnt advise to crack out the 600w hps, it will probably burn the plants even from far away , and given that light diminishes exsponenially it would waste the vast majority of energy fuelling the light, and plants can only grow so much, your way better off looking at the c02 in the air, nutrients, air flow, ext,
and remeber that given its mainly only using blue light, the photosynthetic active radiation is goin to be extremely small by using HPS
so all in all, you can but it will waste about 90% of the electricity ur pumping into the light
hope that helps
cheers

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