you can do 18/6 when ever you want. you can even have that light regiment starting seedlings. it is only highly recommended to keep clones under 24hours, but 18/6 will do too. myself i was using 24 hours with my mh with bigger plants but now im going to switch to 18/6 cause my electric bill is getting really high. but when i use my t5 at start of seedlings or clones i will use 24hrs cause t5 take less electric. just remember

vegetative stage : 24 hours or 18/6 - whatever your preference is. some people say there is no noticeable growth either way and some say there is faster growth with 24 hrs cycle.

Flowering Stage : 12/12 - you only use that light cycle when you want to start to flower. mostly done when the plant reaches atleast a foot tall but will get a better yeild if wait till you see pre-flowers

** just dont keep switching back and forth from 24 to 18/6 and so on. it will cause light stress causing it to herm.
cigarettes42 Reviewed by cigarettes42 on . How Much Light Should You Give a Seedling? ok, i have 3 seedlings right now that just sprouted, they are all about a half inch tall. How much light is recomended for healthy strong growth? Its been about a day now and i have my cfls goin 24 hours what shud i do?:wtf: Rating: 5