Stunted Growth

so this is my first grow, im about 4 or 5 weeks in and im growing 4 Indica's started from seeds, using a perlite/soil mixture, 4 100 watt bulbs and a 6.7-7.0 Ph 10-5-14 NPK Growth Nutrient for watering. i had read online how to tell when the plants need to be fed by simply sticking ur finger a lil ways down in the soil and if its still moist ur good, so ive been using that trick which normally results in water every 2-3 days. So as shown in the pictures below all the plants are a beautiful healthy green and 2 of them are growing great, but within the last week or so ive noticed the other 2 havent really been growing and 1 seems to be bushing, so i lifted that light to try and get those 2 to stretch and they havent really done any stretching either, i dont know what else would really cause them to bush. i keep them on an 18/6 timer ive fed them all the exact same amount with the same amount of nutrients, nothing has been different between the 4. Need some pointers on why they arent growing and how i can get the 1 to stop bushing. Also any pointers on what i could change or things that might work better than what im doing would be greatly appreciated.

Uh . . . . they are bushing because the roots are filling the space. Prepare to transplant by the way. How long were you planning on growing them in party cups?

the 2 that actually are growing (the big ones) i was planning to transplant today actually, but since the other 2 really arent moving past the rim wasnt sure if i really could.

How are your temps with 400w of lights? If those cups are warming up the roots won't like it. Only thing I don't like about solo cups, in the heat they can warm up too much I have found. I had to bury my last lot in a tray of dirt. Shoved my thermometer up the drainage hole of a cup and the temp was 54c

It would have been better to let the plants use only the available nutes within the soil mix.
Most soils can sustain a new plant up to week 4 or 5. No need to drown them with feedings.
I also noticed that each cup is only partially filled with soil and have less space for emerging root system.

You should have only lightly watered them and once they look around 2-3 node in growth transplant them into larger pot. Right now they are getting stressed from such a small container AND lack of room.

As far as your lighting - at LEAST put a one bulb over EACH plant. ( 2-3 inches )

Okay so transplant big option and as far as the temps im using CFL's so they dont really get that hot normal temps are between 75-80F at 25-30% humidity.

Using CFL means u have to compensate for its lack of penetration by placing them close.
I use CFL as a STARTER for my girls ( because my lights are a little much when young )
Check your spectrum also - i use 5000k or 6400k Feint Electric.

Easy way to start your plants WITHOUT drama.

Yeah it does not take much for those little cups to heat up (compounded 10 fold with dry soil). If your lights are actual watts, 400w will still be giving off a bit of heat.

If the cups feel slightly warm, then they're probably too warm.

i am also using 5000k's the only reason i moved them farther away was because i was trying to get them to stretch then move the lights closer again but that didnt work =P

Okay so guess general fix seems to be transplanting them and i "should" be okay. Anything else you guys would suggest to change or fix? This being my first grow im willing to take any pointers i can get to stay away from the nightmares that alot of people have.

Yeah for sure. See Budz' pot in the pic above? That's about the size I'd be looking at.

Also see how Budz has watered the plant around the stem... that's how you don't over water when the plant is settling into the new larger pot

Okay Cool. Thanks a ton for the help and the advice. Some great information and big learning process for me

So i transplanted them into 1 Gallon pots, transplant went fine and while they were out i took a look at the roots and they all seems to be in good shape, nice and spread and not overlapping or circling at all. Again thank you for the help guys,hopefully this solves my bushing problem and stunted growth on the plants in the 2nd picture.