Induce Flowering Prematurely Outdoors? Need Information... + Rep

I know it is possible to induce flowering on an outdoor plant prematurely by covering it so it only gets 12 hours of light, but do you have to do that everyday for the flowering period?

Or can you just cover them for a couple weeks and then they will be far enough into flowering to not switch back to vegetative growth?

The problem is that my plants will be freaking trees if I wait for them to switch naturally.

Thanks.

I heard that at least 4 weeks is needed.

After 4 weeks, a lot of indica strains should be fine.

On the other hand, sativas can be more sensitive to photoperiods, and I wouldn't recommend removing a sativa from 12/12 at all.

Like, maybe the last week for a sativa.

it depends on how far your into the season outdoors for example lets say your at the start of your grow season where your daylight hours are like 15-18 then your plant would try and reveg once u induce flowering but ... if u induce the 12 hour light cycle and once u see them sexing and your daylight hours are comming down u might be okay.