If you want to make lots of money selling vegetables and fruits in Stardew Valley, you have to know what the most valuable crops are. This article lists the buy and sell prices for vegetable and fruit seeds, so you can plan your crops for maximum profit. The highest selling and most valuable crops are in this order:
Rare Seeds (Buy for 1000g, sells for 3000g)
Pumpkins (Buy seeds at 100g, sell pumpkin for 320g)
Melons (Buy at 80, sell at 250)
Blueberries (Buy at 80, sell at 80, but you get multiple harvests from one plant, so the return is significant.)
Amaranth (Buy 70, sell 150)
Yams (Buy 60, sell 160)
Potatoes (Buy 50, sell 80)
Radishes (Buy 40, sell 90)
Eggplants (Buy 20, sell 60)
Cauliflower (Buy 80, sell 175)
These are the best crops to plant overall.
To break it down by season.
The best crops to plant in Summer are melons.
The best crops to plant in Spring are blueberries.
The best crops to plant in Fall are Pumpkins or Rare Seeds.
Hops are also a strong summer crop if planted early, thanks to their multiple harvests. Corn is one of the fastest growing crops, and it grows for two seasons, so you will also get a good return on that.