go kelantan, see singboard 'pertanian adalah ibadat/sedekah'

din recall the correct word.

becuase a tree u plant, whoever benefit from it, already a sedekah in itself, the birds, worms, animals, human taking shade under the tree... everything counts.

no need until directly wakaf already so much pahala.

im not sure u can specifically ask anyone wakafkan their belongings, what do u expect the reply would be?
not nice to make anyone in difficult situation. best sedekah is to be done in secret.