You should feed at around 3 weeks, and I would order nutrients online. For around $50 you can get a 3 part fox farm pack, It will last you a couple grows.
by feed you mean leave the lights on i think, and yes if you want to switch you light cycle to 18/6 should do it now, the sooner the better unless you are flowering. That a whole dif realm
IMO, nutes are nutes no matter what brand, so unless if going organic, I'd buy a cheaper nute set than FF that has the same chemicals, but ff stuff is usually Ph balanced which is a cool bonus And what soil are you using ? If ffof I'd probably wait 5-7weeks before adding any extra because the soil is already loaded
sit back and be very calm. you can prepare for nutes when you hit flower, feed 1/4 the amount suggested on the container a week before flower to prep. then step it up.
Looking good so far~ just wanted to add my .02 worth about nutes. I agree to wait because there are nutes in most soils (MOST soils, like FFOF, etc.). And I always start nutes @ at least 1/4 - 1/8 strength and go from there. Better to under feed then over I always say.
Check it out http://forum.grasscity.com/indoor-marijuana-growing/1098658-check-out-my-auto-weekly-updates-2.html [ame=http://www.youtube.com/watch?v=vjKXBzTgoxw]First Grow 5 Weeks Old Auto #1 - YouTube[/ame]
I got Alaska Fish Fertilizer from home depot, all organic it seems to work well. I use it for the veg cycle, and I got a sack of pure jamaican bat guano for my flowering stages lol huge buds!
lookin good, your gonna wanna stop feeding nitrogen in a week or two and up your phosphorus and potassium. they have super bloom at armstrong and homedepot its 12-55-6 idk if your trying to go organic though but thats what i use to use. just make sure u flush a week before u harvest and you'll be good