how many lumens is enough?

doingfine

Well-Known Member
im ready for growing stage , can anyone tell me im growing 3 plants 18 inches high is too many lumens too much? is their a limit? how far should i keep these lights to the plants? im using 400 watt high pressure sodiums for the tops and was gonna use some t12s on the sides while i rotate the plants?
any help would be great
 
400 will be fine but 600 or 1000w would b better.
keep the light 6 ft above cuttings/seedlings and gradually lower it over a week to 2ft above cannopy.
 
General rule of thumb:
3000 lumens/sqft for vegging
5000 lumens/sqft for flower

While I think 6' is a bit high, do start well above and gradually lower the lights to just high enough to where they don't burn.

I don't think the T-12's will be of much benefit. Not if the plants are only 18".

Wet
 
If you have T12's ALREADY, use them as side lighting as you planned. However, if you are going shopping, get at least T-8's. Wal*mart sells 4' T-8 lights and bulbs for under $10 each... I would not use 1000w on 3 plants. that is just overkill and will prsent new problems, such as getting rid of the heat generated. I've also never read or advised anyone to keep a light 6' from a plant top..... what's the guy got? 10' ceilings?
 
If you have T12's ALREADY, use them as side lighting as you planned. However, if you are going shopping, get at least T-8's. Wal*mart sells 4' T-8 lights and bulbs for under $10 each... I would not use 1000w on 3 plants. that is just overkill and will prsent new problems, such as getting rid of the heat generated. I've also never read or advised anyone to keep a light 6' from a plant top..... what's the guy got? 10' ceilings?

6ft above cuttings or seedlings it said as you will burn them to death otherwise.
 
do t8's produce more lumens?
and how do you know if your burning the plants?
so i would assume that 2 400 watt sodium is fine with the t8's for what i have?
thanks guys for all your help
 
do t8's produce more lumens?
and how do you know if your burning the plants?
so i would assume that 2 400 watt sodium is fine with the t8's for what i have?
thanks guys for all your help

The only real difference between t5, t8, and t12 lights is the diameter of the bulb. The t5s are 5/8", t8s are 1", and t12s are 1 1/2". The t5s are better for growing because they put out more lumens per square inch.
 
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