I grow some veggies and have always wrapped the trumot 1%+ and discarded it after the berachah. Now I have a compost bin with earthworms than make the compost from organic waste I give them. Can I toss the trumot in the bin if I will use the compost to enrich my soil?
It is permitted to allow the terumot to decompose, and then to use them as compost. However, it is not permitted to speed up the decomposition of the terumah by using earthworms (or other catalysts; see Chazon Ish, Demai 15).
Sources: It is permitted to derive benefit from terumah tehorah after it has become unfit for human consumption. See Sefer Eretz Yisrael (151), where Rav Tuchutzinsky recommends using oranges after they have rotted as fertilizer. See also Ha-Torah Veha-Aretz, vol. 4, p. 115-120. However, one may not speed up the decomposition process of terumah, for this would be disrespectful to the holiness of the terumah.