How will you differentiate between two vendors who sell organic Tomatoes at the same price? As long as the customer gets the tomatoes, does it matter? I am just trying to understand the value. Or do you only facilitate transaction between a vegetable seller and a buyer who already is a customer to that specific vendor (presumably from previous visits)?
" pick out the their veggies being very particular" - Do you mean you pick their veggies IN particular. For example you will pickup Organic Cabbage from A SPECIFIC vendor, Tomatoes from ANOTHER Vendor and such? IF that is the case, I see two issues:
Organic farmers that come to these markets do not have produce in such volume to cater to many many households. If I got the farmers market at 2pm on a weekend, most of their produce is sold out.
Second point is more a process point - I understand you are using farmers market as a metaphor, but is there a need for you to be physically rooted to the markets? Most of the farmers truck their produce very early in the day (4-5am) and come and setup shop in a farmers market by 7am. Would it not be efficient for them to send you their prices (Text or App) 30 minutes before they leave and you can tell them "You are the one we are going to be picking up tomoatoes in bulk from today. So bring extra". Or even pushing the case further, would it make sense for them to just come over to your office and give the tomoatoes, skipping farmers market entirely?
In India, where I am from, a vegetable vendor comes with rolling a cart full of vegetables from the market and my mother buys from him. He comes at 7am. Is this something similar? Agreed you don't come in rolling cart, but you get the idea.
It is difficult to get the economics right if you are dealing with veggies. The number at which you would turn profitable would be the number where people will choose other options. It works for groceries bcos the economics still look ok