you need some stronger lights there. that is some extremely severe stretching...
do i see halogen lights in there? if thats so then thats a problem as well...halogen's give off a LOT of heat and not a whole lot of lumens.
you either need cfls...if you want them small get the 23w version...the have 1600-1750 lumens. otherwise get a 100 something or higher watt cfl...they have more lumens and you can use less of them. cfls are good as they do not emit much heat so they can be placed REALLY close to the plants....the downside is you are getting a whole lot of lumens...cfls are better as side lighting or supplemental lighting....not as you main source of light...they will produce marijuana but not nearly as well when compared to mh/hps bulbs
if you have a couple hundred bucks get a hps/mh system. while this is more expensive to buy (and operate regarding the electric bill) its also worth it. you get twice as many lumens per watt (or more in some cases) compared to cfls...a 600w hps gives off 90,000-95,000 lumens.how? well a 23w cfl that has 1600 lumens is giving 69 and 1/2 lumens per watt...the 600w hps is giving you 150 lumens per watt (if its a bulb giving off 90,000 lumens) to 158.3 lumens per watt (if its a bulb giving off 95,000 lumens).
so to match a 600w hps (with 23w cfls) you'd need 55-60 of them...who's gonna do that? or who can afford that bill? the idea is you'd have to spend twice as much money in running cfls (on your bill) to match an hps...therefore (overall) hps is the most rewarding way.
take it from me. i started my first grow with 23w cfls...i used 10 of those bad boys for just 2 plants. i vegged a whole month and they were less than 1ft tall...i think my biggest was around 9 and the little plant was only 6 1/2-7...i vegged 1 month and 3 weeks to get my biggest one at 12 inches...i figured this to be unacceptable.
here in my second grow i've vegged 6 big bang fem seeds for just a few days over 2 weeks (i think like 3 days) and the biggest one is already nearly 1 ft tall...i think its 11 inches today. therefore (if they grow as they been) by the end of just 1 month veg they will be almost double the size they are right now...so i could possibly be looking at a 2ft tall plant...and saving myself 3 weeks of veg time.
i've never flowered with cfls though...before my first plants went into flowering i got the hps...they went from being 1 ft in 1 month and 3 weeks to being 3ft (sativa) and 2 ft (indica) and i still have 2-3 weeks of flowering left. they did that huge spurt all within the first 2 weeks of the hps being used on them.
so take it from me. if you have the means (cash) and the place to do it (as it appears you do) then i urge you to get an hps...even if its just a little 250w or 400w. keep in mind a 400w hps generally only should be used to grow 4 plants...a 600w = 6 plants...1000w = 10 plants...so each plant should get 100w of hps light...so keep that in mind when purchasing...
also PLEASE keep in my hps/mh bulbs and systems get REALLY hot. my 600w hps is digital (not magnetic ballast) which is believed to run cooler...while i do see a difference it still gets really hot. so if you live somewhere that gets really hot in the summer (im talking 95 degrees and up) you should really invest in air conditioning (if you dont have one) before purchasing...remember that plants dont like severe heat (at least not mj plants). if you live somewhere that peaks around 85-90 in the summer then you might have a chance with good ventilation and fans...
hope this helps...