Hey there BeginnerBuds2020, here’s my thoughts on your issue... your plants will remain in the vegetative phase almost indefinitely until you change/reduce the light cycle (18/6 down to 12/12). This is what allows breeders/growers to keep a desirable "mother" plant alive while continuously cloning thus keeping the plant/phenotype/strain going indefinitely. You will start to see pre-flower begin shortly after reducing your light schedule. I generally feed a 50/50 mixture during the pre-flowering phase because the plants still require a decent amount of Nitrogen to power through the flowering stretch. Once they have fully begin to flower with well formed puff balls of pistols- I begin feeding them a bloom fertilizer. Base your timing on what you see with your plants rather than a schedule/label on a bottle. Your plants will pretty much tell/show you exactly what they need and when they need it. I think your plant(s) look great and you’re well on your way to a successful grow and a great harvest! Awesome job and all the best growing forward! 🇨🇦