Fred would borrow those tomatoes at an agreed price. Freds neighbours would not accept a lower price for those tomatoes. He would repay those tomatoes at either the agreed price of a higher price or alternatively fred would grow tomatoes before the loan expiry to hand them back.
If he does this and regrows tomatoes he is a producer NOT a shorter, shares cannot be produced through photosynthesis and fertilisation.
Shorting is about betting the re-purchase price will go down, what your analogy suggests is fred is wanting to borrow something and sell it higher for profit NOT BUY IT LOWER in teh hope of selling it back to the lender cheaper for a profit. That is not shorting.
