We all advocate for change but do we really embrace change? Convincing people to invest in Bitcoin or exchange goods or services with Bitcoin is not an easy task, especially for the novice.
Firstly, You gave customers the opportunity to buy your farm produce at a discounted rate using Bitcoin but did you consider if they have a wallet? The answer is probably NO especially the "not so young" Some may not have even heard of cryptocurrencies while some may have heard but don't know how to go about it, now to convince them to own a wallet is not child's play because some people tend to focus on the negatives more than the positives.
To achieve this successfully, you need to consider your location, know your customer, know your market target, target age, etc. Then make the payment plan as flexible as possible, you should not limit it to Bitcoin.