Bench VS. Prone

[trammerbammer]

I'm not sure if this is where this topic is supposed to be, but if its in the wrong place oh well. I've zeroed my scope while using a bipod while laying prone. I took my rifle to a range for the first time ever, and I'm getting groupings 4 inches high, and 2 left. I have been told that is because I've set up on the grass, and the recoil is taken different on a bench. My question is this: If I zero my scope at the range, will it be zeroed on grass. Any input would be great, thanks.