It looks like your plants suffer from a Magnesium deficiency. If i were you, i would take care of this prior to switching to flower because in flower they will burn through magnesium even more, especially the first week to 10 days! Foliar feed is the easiest and fastest way to have the plant take up the additional magnesium. Good luck! Other than that they look good!
I had the same issue with my Green Gelato’s and fixed it within a few days after supplementing them with cal/mag boost. Goof luck with your grow and keep ‘m green! 🌿 MG
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