How long to notice changes after the switch?

Its 7 days after the switch now and just wondering when i should start seeing changes? Ive noticed the girls have started to grow jaggedly instead of straight up and the growth looks more bulkier, like tighter together if you know what i mean? I shouldnt be seeing drastic changes after just one week should i? Heres a pic anyway of one of them! Thanks in advance! Sorry about the lights being on aswel!

idk what your definition of significant is, but the first two weeks or so of flower is usually the stretch phase, where the plants will double or maybe triple in size.. the pistils start, but usually won't see what looks like nice buds till about 5 weeks or so into flower for an indica dom strain, then from that point they pretty much just fatten up for the last few weeks..

Depends on the strain and grow setup. Usually week 1-2 your plant fills out and gets bushy then you will start seeing either pistols (hopefully!!) meaning its a female or pollen sacks meaning its a male. It looks like you already have pistols showing which is a very good sign. Usually by the 3rd week you can tell a difference in your girl every day or two with the bud sites growing more pistols and getting bigger and fatter.

Thanks for the info! As for the set up ive got two 400 HPS's, air circulation is bang on with the temps constantly at 24 with lights on and around 17 and lights out. Pistils showed in veg at around 5 weeks...The girls dont seem to be growing in height alot but u can see them stretching for the light around the sides, there just getting bushier if anything! just started the big bud today at quarter strength of my base! (currently 25ml Canna A&B)

Again thanks for the info people! appreciated

forgot to mention the RH which is around 35-45% and the strain is G-13! Thanks