vertically challenged plants

So I'm new to growing this but I've done more reading and research about this than I did in my college Chemistry class. I have four little ones, green as can be, healthy as ever, getting thicker by the minute, but they're short. As of today, I'm at day 25 from the time I planted the germinated seeds, and the tallest plant is only 5 inches from the bottom of the soil to the top of the plant. The other 3 plants are between 4 and 4.5 inches tall. Here's my set-up:
Indoor closet environment; the closet door is always open though so they get plenty of CO2. Humidity around 50%, day-time temp 73-77 degrees, night-time temp 67-70 degrees.
Soil - Miracle Grow Potting Soil (I know everyone hates this stuff but it worked great for many harvests before with a buddy of mine) and I added in Perlite.
Fertz - As of right now, I'm not using any fertilizers because M.G. already has them in it, and I'm afraid to kill them. I have, on the other hand, added about 1/2 tspn of Epsom Salt per 1 gal of DI H2O (I was told M.G. soil doesn't have much Magnesium in it) and use that when I water.
They have all been transplanted into individual 1.5 gal potters.
Lighting - Here's where I think I'm having my problem. For the first week and a half, I was using one single energy saving light bulb from the local store, a little one, output of 16 Watts or some shit like that, it's little, trust me. For the past week I've had the little light and an LED growing ballast set-up, and the plants love it. They've gotten thicker, spanning leaves, more leaves sprouting out the top all of the time, but they're not getting tall at all. The plants are in a big ass plastic bin that is 90% covered with aluminum foil (shiny side facing the plants) and it's illuminated like crazy. So I'm thinking maybe I just don't have enough Lumen-output?
Or maybe i need a growth enhancer/fertilizer?
I dunno. Any help would be great.
Oh, and I have no idea what kind of seeds these are. They're from a sample of stuff I had that I absolutely loved: Really strong cerebral high, but focused, NOT lazy at all; just made you want to smile all day and go out grocery shopping. HAHAHAHA.
Thanks y'all.

More light and bigger pot of soil = bigger plant.

you are better off if your plants branch a lot early: = more buds

that they stay low might be explained by their genetic heritage or the little amount of light they get. some strains like to shoot in the air when they start to flower (like power plant)

but one thing i gotta say: watch out for hermaphrodites. seeds in weed are often the result of hermaphrodite plants, which in turn produce seeds with a tendency for hermaphodicity - so watch out for male flowers and remove them early.

werd, thanx dude. BTW, i'm a HUGE Meshuggah fan, so I love your post name.

as long as they r producing nodes all is well , shorter the better with plenty of nodes is cool man.

I would be careful about having the shiiny side of teh aluminum foil facing your plants, I heard that it can cause hot spots and burn the leaves cus by focusing the light like a magnifyig glass. Not sure, but I always put the dull side facing the plants, and it reflects enough light. Just a heads up.

There's plenty of nodes, it's short and full. I just added more light... and they grew 1 inch in 7 hours, so I'm thinkin that was my problem. And I'll fix the foil thing for now. I'm going to build a box and paint the inside w/ Mylar, or flat white paint, one of the two. Thanx y'all.