How much horse manure should I use for potted tomato plants?

I'm not sure what the soil to manure mix should be. Any help would be appreciated.

How much horse manure should I use for potted tomato plants?
If the manure is well rotted/composted use it as a top dressing. An inch or two on top of the soil around but not touching the plant and you don't have to worry about using to much and burning roots. The nutrients will work into the soil with waterings. Even though horse manure is not as hot as others don't use it green.