HARLEYVILLE, S.C. — After Hurricane Dorian battered his farm in September, John Trenton Pendarvis faced a costly decision. Dorian's winds had blasted the hemp he had planted in early summer. On one particular 10-acre field and its nearly mature crop, he had already spent over $75,000 for licensing, seeds and labor — a sum that he hoped to recoup by selling the post-harvest hemp oil and flowers for several million dollars.