If you're looking for manga similar to GREEN - I Wish to be a Farmer’s Wife, you might like these titles. All recommendations are made by Anime-Planet users like you!
In both series a city person comes to countryside and gets involved with farming. Main characters in both series represent their respective target audiences (teenage guy in Ja Ja Uma Grooming UP! and woman in her early 20'ties in GREEN). Both series feature a fair amount of comedy and some romance. Speaking of which, GREEN has inversed proportion of romance and farming in compare to Ja Ja Uma Grooming UP!
Anyway, if you liked the themes I mentioned earlier interesting, then both of those manga should prove satisfying.