There is no need to use herbicides since there isn't any soil in the entire greenhouse. Tomato World doesn't advertise. Clyde is clever in his marketing strategy with the area supermarkets. To promote his hydroponic tomatoes, he slices the tomato and has the produce manager taste the great flavor. Then instead of just letting the tomatoes sit on the shelf with a price, he insists on setting up and manning a tasting booth himself.
Customers come by, comment on the high price but taste a sample anyway.
They would look the other tomatoes over and eventually make their way back. They'll last up to two weeks if left at room temperature. And so another marketing promotion appears. Clyde guarantees his tomatoes. If any of his tomatoes that weren't refrigerated spoil before two weeks, he replaces them pound for pound on the next order.