Im germinating my seed in tissue now and i have a 400w hps light i was wondering if 20/4 was best to start them before switching 12/12
Keep your light on 20/4 or at least 18/6 throughout the whole grow. Some people start them out with just some cfl's for the first week I run a 400w HPS also and I start my auto's with it just be sure to hang it at least 20" from them. Also no need to go 12/12 this will harm your yields. I find 18/6 is optimal with the strains I have tried, ymmv though.
okay thanks do u no what yeild i could be looking at once dried this is my first grow so dont no much
The nice thing about autos is it make for an easy perpetual garden. Since you never need to change you light cycle you could start a couple seeds every couple weeks that way after 60-90 days time you can pull a nice little harvest every couple weeks. And if you grab yourself some non-feminized autos you can do a seed run first to get a couple hundred seeds so you only need to buy when you want variety.
how do u min the hight i dont think auto northern lights grow that tool but the rooms height im doing them in is 6foot tall