Here is an idea I just came up with that could be really handy for gardeners and farmers alike!
There could be a button in possibly the settings page to start or reset reward tracking. If I press that button and then I harvest all of my plants, I will see an easy to read, itemized list of everything I have been rewarded since I last reset. This could also be useful for farming. After farming for an hour, I could easily see exactly how much of each item I received without knowing how much I had before farming.
This could be laid out similar to the sort of "summary" seen when quick selling items, but obviously there are a million different directions developers could take this.