A.T. Robertson Commentary Luke 13:8

"And he answering saith unto him, Lord, let it alone this year also, till I shall dig about it, and dung it:" — Luke 13:8 (ASV)

Till I shall dig (εως οτου σκαψω). First aorist active subjunctive like βαλω (second aorist active subjunctive of βαλλω), both common verbs.

Dung it (βαλω κοπρια). Cast dung around it, manure it. Κοπρια, late word, here alone in the N.T.