Using a Harvester promo code is simple and can be done in one of two ways. First, you can show a Harvester coupon to your server at a restaurant. Second, use a Harvester voucher in the app or online for takeaway orders. Here are the instructions. Cop the Harvester voucher code you wish to use. Browse the app for takeaway, or visit the site to reserve a table. Before you confirm your order or booking, apply the coupon in the voucher code box. Your discount will be reflected in your order summary.