How to stop a While loop when an object reaches a certain size?

I am just beginning to learn coding, I am currently messing around with a block of "grass" that increases in height every 5 seconds.

While true do wait(5) game.Workspace.Part.Size=game.Workspace.Part.Size+Vector3.new(0,0.2,0) print("grass has grown") end

this works perfectly, except it keeps going on forever. What I want to learn is how to phrase the While statement to stop when the part reaches 2 studs tall. I have tried the does not equal, but I am not sure how to phrase that to check the Y value

While game.Workspace.Part.Size~=(2) do wait(5) game.Workspace.Part.Size=game.Workspace.Part.Size+Vector3.new(0,0.2,0) print("grass has grown") end

But that code doesnt work for what I need it for, and if I try

While game.Workspace.Part.Size~=(0,2,0)

it doesnt recognize it as valid.

Why don't you use an iterative for loop? It's definitely simpler than a while loop.

local grass = workspace.Part
local goal_height = 2
local increase = 0.2
for i = grass.Size.Y, goal_size, increase do
	wait(5)
	grass.Size = Vector3.new(0, i, 0)
end
print("Grown.")

Basically, it'll loop up to your goal size. Each loop will happen five seconds after the last one. This is basically what this kind of loop was designed for, so I don't see why you wouldn't want to use it. If you're still wanting to use a while loop, it's just a simple check in the conditional:

local grass = workspace.Part
local goal_height = 2
local increase = Vector3.new(0, 0.2, 0)
while grass.Size.Y ~= goal_height do
	wait(5)
	grass.Size.Y = grass.Size + increase
end
print("Grown.")

Best of luck!

While true do
    wait(5) 
    game.Workspace.Part.Size = game.Workspace.Part.Size+Vector3.new(0,0.2,0)  
    if game.Workspace.Part.Size == Vector3.new(0,20,0) then
         print("Grass has fully grown!")
         script:Destroy()
    end
end

What I just did there was add an if statement to see if the part size is 20 studs. And the destroy means...it will destroy the script. This script may not work as I am also new but it should.

Hope this helps you.