1st grow need feedback please

i like to fist say please send ur feedback as to what im doing wrong and what i could possibly do to improve and my main thing is when and what i should feed em . (please excuse my writting cause english was 1 of my worst subjects so bare with me please)
so i first germinated some bag seeds on oct 6. they sprouted on oct 9th and then i moved them to the jiffy cube. once they got a lil bigger i moved them to the beer pong cups (red party cups).
now im useing mc garden soil , mc perlite,and there under a 400w metal halid and the timer is on a 18 6 . ive been checking the ph in the water and adding lemon juice to bring the ph to 6.5 to 7 that all ive done so far more to come on the progress of the plants

the 2 cups with out perlite are my first trail and the big one seems to be doing ok i guess but the 1 with perlite is the newest 1 that i put into soil yesterday oct 10th and ima wait to till it gets a lil bigger to move it to a party cup so please send ur feed back and questions thanks
also please let me know what ferts i can use to feed em ferts i can buy at a home depot and i forgot to say here are some of the stuff i got

you should water when the top layer of soil is bone dry...im pretty sure those moisture crystals arent helping...if they constantly retain moisture thats not good for the roots

you shouldnt giv em ferts yet. ther too young. u should wait lik 2-3 wks.
water should be good for now
jus my few cents.

jah.

after the 3-4 week what kind of ferts should i get

Higher up the light 18 inches,from the top of the seedling..Add gardenlime to the mix http://www.google.com/products?hl=en&rls=com.microsoft:*&resnum=0&q=espoma+garden+lime&um=1&ie=UTF-8&ei=2JLSSouqOo2EswPTjaTwCw&sa=X&oi=product_result_group&ct=title&resnum=4&ved=0CCEQrQQwAw .I use kelp,a lil bit of compost, and this for veg..http://www.google.com/products?hl=en&rls=com.microsoft:*&resnum=0&q=miracle+gro+houseplant+food&um=1&ie=UTF-8&ei=C5PSSrW4K4nqtgO7iujvCw&sa=X&oi=product_result_group&ct=title&resnum=4&ved=0CCYQrQQwAw

get a fert with micronutrients for veg not bloom.
get shultz or peters ferts.

jah.

So its been a while i havent been keeping track of my girls like i wanted neways i been useing fox farm grow big, tiger bloom, big bloom,and beastie bloom. Through out this process ive been haveing ph problems in the soil , the ph is fine in the water but been dripping out of the bottom and reading below 4 so ive been adding a stronger ph to the plants not sure yet on how its working but the 2 plants seem to be doing good and the smaller one idk i think its on its way out the door