You are missing that you are using L85 seeds. They give crafting XP for 10 levels - same as you get no crafting XP for making foods or potions which are 10 level below your crafting level.
It should remain the same in next L85 zone, there won't be new mats so no new seeds. Next zone after that is expected to be L87, but it may or may not introduce new L87 mats. If not, then there wont be new seeds then either, and you would have to wait till L90 zone for new mats, new seeds and new increase in planting level.
Some of it is speculation, sure, but not an unfounded one.
-- Rustyx --- 92R / 92S / 92M on Reni (Guild KnightShift). Yes, running the new FOTM R/M, cause I am not elf enough to be WD/S.
Oh, and people who have more than 3 classes are clinically insane.
This post has been edited 2 times, last edit by "vfwiffo" (Jan 6th 2014, 11:45pm)