Problem placing something in the middle of a part along the Z axes

Hello everyone.
I’m working on a farm system and I’ve come across a problem I can’t seem to get fixed.

basically this is a farmland
Wherever the seeds get placed, they will be along the middle horizontally like in the picture below

I do that by doing

local Angles = Originalcframe - Originalcframe.Position
SeedCFrame = CFrame.new(Vector3.new(Originalcframe.Position.X, Originalcframe.Position.Y + Seed.Main.Size.Y/2, ObjectToPlaceTo .Position.Z)) * Angles

And ObjectToPlaceTo its Z axis is this so it will be in the middle horizontally.

But if I rotate the part, the Z axis will be like this


Only placing it along the line.
And no longer horizontally relative to the farmland.

Anyone who can help me out?