How can I pass the cost of packaging on to my customers?

Your customers are already paying indirectly for your raw materials, your staff payroll, your rent, your electricity, and your delivery costs. Packaging expenses are merely another running-cost component that needs to be considered before setting your selling price. Well-designed packaging is unlikely to cost more than the packaging used by your competitors – unless it is notably better, in which case you can congratulate yourself for creating a valuable point of difference.