Ok so I use Wilton colors for my fondant (pretty much the only thing I can buy, unless I shop online and no time for that)

So I can't seem to find a lime green...the lady at michaels says she is sure they don't make a lime green.

So I have most, if not all the wilton colors...what can I use to make limegreen? Will leaf green with a little of the lemon yellow work?

yes. leaf green and lemon yellow will do the trick

A lot of yellow in ratio to a little green. green is a stronger color

I agree....more yellow than green. I have bought a neon green from Decopac and its the perfect lime green.

In class tonight, someone made lime green with lots of lemon yellow and a tiny amount of sky blue. It was a really cool color!

One thing I have found that helps when I am mixing fondant colors is to actually make the colors seperately in fondant than mix those together. So I would make some yellow and some green then blend small amounts together until you get the color you want.