I've created some grass in the hair room using the "ground" as base, I have animated it for 30 frames. Everything works fine. My question is my full animation is 1023 frames long, can I reuse the same simulation of the grass over and over to fill up the 1023 frames or do I have to calucate the dynamics for each frame? I parented the grass to a small box then saved the animated pose to the pose library, and tried to add it to the next 30 frames, but that didn't work

I am trying to make the grass  look as if a small lite breeze is moving it

You could use a magnet on the Hair group (avoids the need to simulate), but you'll need to keyframe either the magnet position or the magnet effect dial as required during your animation.

or you can use the wind generator,works perfect for (hair)grass.

Thanks for the info
I am not very good at magnets and have never tried the wind generator, but hopefully I can get one of them to work like I want
Thanks again