Someone stole into the garden and picked it clean.
A local guy-- a farmer I presume-- heard the story and gave a huge portion of his harvest back to the group so they would still be able to make the donation.
Take that you dirty thieves!
Self-reliance is not synonymous with stingy selfishness, or being greedy. No doubt what the farmer gave away was not "surplus." Most likely, he had planned on benefitting from his entire crop, and hadn't planned to give a portion of it away.
Or maybe he had planned for some unknown. I'll never know. But I think I'll plant a bit extra in my gardens from now on.