Gilbert is the owner, just you need to pay him to collect the onions. Do you have the money to pay him? Do you have the tool needed? Did you pay him already? Then go there are harvest the onions.
Yeah but wth. I have a hoe, I payed him a while ago and even am carrying 48 extra coins. He is on the farm and I see the unions, I click to hoe them and it says that I have to "Find the owner and agree to help him", which is something I did a while ago with Gilbert. The only prompt with Gilbert are "Where are the communal farms?" and "I don't have more questions at the moment." I am serious, I have everything and I'm sure I did everything. Gilberrrttt, why can't I get what I paid for. ;-;