T5 ventalation

[Roughrider]

p.s.If i was using a 2 foot 6 bulb t5 that put out 1300 lumens how many plants would i be able to grow under it until they are ready to harvest And how tall can they be?

Short answer: not many.

Long answer: You're talking about 12,000 lumens with a 6 bulb, 2 foot T5 setup. My guess is you're looking at something like this:

6 Lamp 2' foot T5 GROW LIGHT with MIXED VEG BLOOM BULBS - (eBay item 180194886756 end time Jan-12-08 12:05:00 PST)

That's enough to do a good job on two (2) plants through flowering in an area of about 2.4 sq. ft. If you're thinking about flowering 6-8 plants, you'll need at least 8 sq. ft. 10 sq. ft. would be better. That's 50,000 lumens to do a good grow. So, for T5 set ups, you're looking at something more like

8 lamp T5 High Output T-5 grow light eight MIXED BULBS - (eBay item 180150425658 end time Jan-14-08 12:31:35 PST)

That's around 40,000 lumens, which would cover a 48â?� x 24â?� area pretty well.

How tall your plant gets depends on how long you veg, if you do LST, etc.