How long is preflower

So I’m using flora trio and it says to use 1.5ml/L then it says flower 2.5ml/L so my question is when does preflower finish and what week should I start using 2.5ml/L?

When the stretch is done.

Should be the stretch 2-3 weeks maybe

Outdoor or indoor? Outdoor start when first pistol form which in wa state is right now use feeding schedule if indoors

Pre-flowering is the time period where the plant shows sex without being photo Induced into flower, so the days are still long but the plant is now showing it's mature enough to flower if the daylight was shortened. You will see some pistols and hairs in this stage, the plant will stay in this state until daylight decreases. Indoors we sometimes skip getting to preflower and go to 12 12 so quickly you have to look close to find the few sex signals the plant is showing... In this case most will consider preflower begining at the flip to 12 12