gone hydrophonic good nodes should i fert yet?

ok guy ive got ym first ever hydro setup goin via a single oxy-pot. original FLO feminised by dutch passion.

ive got great nodes and the roots have started coming through the net pot now and overall growth is increasing each day.

http://www.growell.co.uk/p/5115/Oxy_Pot_1_Pot_Kit.html

and heres an image do you think i should start nuting?

note: one lower leaf got burnt by a light

also ive now choosen to use bio-bizz organic nutes. grow and bloom ive heard that its virualy impossible to over nutriate with organic nutes? is this true?

cheers for the replies guys