"In Value Deceived" by H. B. Fyfe (1950) may be your answer as per Short story about aliens trading for hydroponics
The alien home world had all its food crops destroyed by a blight. They are surviving on terrible tasting synthetic food which is in short supply. Alien explorers are frantically trying to find an alternate source of food.
They encounter a human starship. When they are invited inside, the aliens are stunned to see a hydroponic garden. This technology is the key to stopping the famine on their homeworld.
But the aliens play coy, pretending not to be terribly interested. Eventually they manage to get the humans to give them a spare hydroponic set up as an amusing trifle.
They give the humans one of their heating units, which the humans had been pretending to be uninterested in. It gives off heat, but also produces ashes. Things like diamonds, gold nuggest, and chunks of uranium. An amusing trifle.
As they depart, the aliens floor the ship's accelerator to run away, before the humans regret their bargain. To their surprise, the aliens see that the humans are frantically running away as well.
The alien captain thinks
“Anyone would suspect that they—not we—had practically committed theft!”