That's a good idea but it will be confronted with a lot of issues but if you are so serious about this, then you can ask a big company that also deals with vegetable to take up with your idea, it will need huge funding but it's not impossible to implement, I hope you will not do an ICO for this, this is a good idea to be ruin by ICO again.
You wont really have any choice if you wont able to get some sufficient support on the big companies you have said.Your option or last resort would be doing some sort of ICO.
It isnt a bad concept after all yet its being said 40-50% save up compared to current vegetable market is really something.The only problem i do see that this would be only
good for those people who are just residing near on OP's place but for far countries it would really be hard since these are perishable things.