[dagobaker]

want to get my plants from my veg room to my greenhouse but its only about 12.5 or 13 hours of sunlight right now.... they are in 18 hours of light right now and they are outgrowing my veg room

[Hazelnuts]

They should flower, 18 to 13 is a big jump, I think they'll start. And if they don't, theyll veg for another month or so and then start flowering

[ChaosCatalunya]

I accidentally flowered most of my nice mothers last year doing this... a major disaster....so now I am flowering a deliberate Spring crop and bringing my mothers/this years monsters in at night for a few extra hours of evening light, a 6/7 hour "night" and an early dawn. I plan to increase the night to 8 hours before putting them out properly in 6 weeks ish so they do not shock into flowering.

Clones seem to be slightly more susceptible to this than seed grown plants, last year Cheese and Diesel clones flowered while Kali Mist seedlings just grew and grew. Obviously this may just be the varieties and my environment, but you do need to watch it either way.

The Dutch do this [extending daylength] in greenhouses with just a few incandescents, it is about extending [the plants measuring of the] photoperiod, you do not have to provide "proper growing light".... although that is going to be appreciated if you can do.

If you put them out right now they will for sure flower.

Chaos was right on the money. Put a small light in your GH and it will keep them from flowering. Try to match up your indoor light schedule to the natural outdoor light schedule as much as possible.

This is what I did in the past:

[dagobaker]

that does make sense i guess
just some floros would probably be enough
keep a light on at night until may 1st should be enough i would guess
after that its 14 hours of sun a day and i should be fine

[trybud]

try to get them adapted to 16/8 then the 14 hour day wont matter. plants going from 24/0 20/4 or even 18/6 sometimes can and will flower when outside. im working on getting my plants to 18/6 right now and by the time i place mine outside (may 15th to june 10th) they'll hopefully be on 16/8 in time with the sun. ive had problems before and ive noticed that a bigger plant tends to preflower up faster and take longer to start reveg when placed outside late april/early may like people around where i live do........

[ChaosCatalunya]

Originally Posted by trybud

try to get them adapted to 16/8 then the 14 hour day wont matter. plants going from 24/0 20/4 or even 18/6 sometimes can and will flower when outside. im working on getting my plants to 18/6 right now and by the time i place mine outside (may 15th to june 10th) they'll hopefully be on 16/8 in time with the sun. ive had problems before and ive noticed that a bigger plant tends to preflower up faster and take longer to start reveg when placed outside late april/early may like people around where i live do........

Originally Posted by DJ_highst_

Try to match up your indoor light schedule to the natural outdoor light schedule as much as possible.

As these guys say, it is not just about giving them light at night, you need to match it to what it is going to get when it does go out full time.

Here are a couple of my ladies, photographed 2 days ago....

A Jordan mum in veg as she comes in at night and a White Rhino [seedling] in flower that has been left out for over 3 weeks.

[dagobaker]

so if i go from 18 hours of veg inside to 14 hours of veg on may 1st outside then i might go into flower?

[ChaosCatalunya]

Originally Posted by dagobaker

so if i go from 18 hours of veg inside to 14 hours of veg on may 1st outside then i might go into flower?

They might, so just reduce the 18 a bit before putting them out and you will reduce the possibility of it being triggered, different varieties will behave differently, I think [but am far from sure...just from observation] that seedlings are less prone to this than clones.

[dagobaker]

going to hang a cheap floro above the plants in the greenhouse for a week or two on a timer to get them use to the light ....that should keep them from flowering