i have couple auto flowers was wandering whats the lowest but best amount of light can i give the flower (t5 lighting fixtures four bulbs)
Are you talking Watts or hours it's at least 125W per plant and with auto flowering plants you could do 12/12 or 18/6 or 24/7 light cycles best one, probably 18/6 although i don't really use autoflowering strains much.
Check with the breeder, the few autos I've grown were recommended 20/4 light cycle. I would consider a t-5 to be perfect for clones and short veg periods, but less than bare minimum for flowering.