We totally understand you wanting more awesome folks to play with, as Bud Farm: Grass Roots is definitely more fun when you're able to visit and help other farmers!
There is a Followers/Following option - this allows players to add others as friends without having a Facebook connection through Budbook! Currently, farmers are allowed to follow up to 10 other players, but can have unlimited Followers!
To Follow someone, simply visit their Budbook page (either by searching for their Username or finding them via Floydslist) and tap the purple "Follow" button (with a star-banner). Then you can just view your Following list to visit those players any time!