Hanging Tomatoes Upside Down How Tall Does A Tomato Plant Have To Hang It Upside Down?

How tall does a tomato plant have to hang it upside down? - hanging tomatoes upside down

I am growing tomatoes from seed, so I have the right to plant tomatoes-side-up hanging over the head. How much should I grow before hanging up?
I am always in buckets and I use Seeds Early Girl.