You can harvest an unlimited amount of items per in-game hour, but you will only receive experience for the first 120 harvests each hour. The counter for harvesting experience resets at the beginning of each hour, and you must be logged in during the change in the hour for your counter to be reset. Once you exceed your maximum harvests in the current hour, you will receive the following notice in red text:
Your harvesting experience limit for this hour expired, you won't get any more harvesting EXP until the next hour.
