im new to this too but i will share with you what i know.1st off,are you spraying the actual plant or the soil.if you are spraying the plant it could be why the leaves are drooping.im told if you spary the leaves you will burn the plant.as for the 2lts bottles,i dont think its a problem with them at a week old but u will need to put them in proper big pots(the biggest pots you can fit in your growroom).if possible bunch them altogether as they all compete with each other to reach the light therefore incourging them to grow faster.also check out the threads i posted asking about light heights and sizing of pots,realy good info.have you a temp and humidity gauge?? i picked up ones for cheap at my garden centre and put them half way up your growroom,helps you keep on track with climate control.
basically keeping the light times strict helps the plant alot so get a timer so its one less thing to worry about. btw all of what i have told you are not facts or maybe they are,i dont no,lol i have just heard these things from this website and word of mouth,well i hope this will help you!! good luck!!!