If you are in soil top them once with a 4 week veg, if in coco top twice. 6 weeks veg would be better, particularly in soil but I understand the want to get them into flower sooner. Try to give them at least one week recovery after final topping before flip. 2 weeks recovery can be better in soil but with only 4 weeks veg you may have to top on 3rd week depending on growth. They should be good to top in 2nd week and 3rd week in coco. Just don't force it if you are not getting quick enough growth. Read more into it and look into journals so you can see how big peoples plants are getting in 4 weeks of veg. You need that perspective to make your own call.
In either case they should yield at-least 20% more this way. But again, if you are not getting quick enough growth do not force it, you'll lose yield topping plants that can't recover in time.
I'm growing in coco this time with 16L Ryhzo pots that came today, I only have one bag off coco "Natural" I hope I can fill all four pots with it, I was growing in soil last time but I ran into that many problems whilst using it son I researched ALOT about coco and decided to go down that route, I have Canna Coco A+B, Rhzotonic, Cannazym, PK 13/14 and boost accelerator, Ohhh and the Canna Flush arrived today to , So I've got every thing I need , I'm growing 2 White Widow and 2 Royal Cheese both from Royal Queen Seeds I do have a extra white widow seed but I'm going to germ it just before these go into flower and experiment with a 12/12 lol
Seen as how in have got everything in need now, I started to germ the 2 Widows and the Cheese , Both are in paper towels and in separate zip lock bags with plates over them and stored in a dry place.
About the topping I topped my Northern Lights I took down 2 weeks ago now (I'm smoking one I as write this to you) 4 I took down just over 2 and a half ounces a plant, I was hoping for more but hey hooo, I've give some off it away to, To my friend for teaching me the ropes but I'd say nice learned more off this forum lol There's some good old Scholl tokers on here with a wealth off knowledge, you been one off them my friend.
So when topping time comes round (it's the training I known how to do) how long shall I veg them for before doing it? Just I'm growing in coco and you only mentioned about topping in soil,
Also can you please answer me this question how long should I veg for my tent is 1x2 1x2 by 200, I just don't want the problem off growing them in veg then topping them then running out off space when they stretch for the first few weeks off 12/12, Another question while your here haha haha im doing your head in now aren't i? One more and ill leave you be a promise, When do you start flowering period the switch from 12/12 or the first sign off hairs around 2 weeks after the flip from 12/12. Thank you for your patience in just want to get eve everything right as you can probably tell lol