Rhubarb Seeds

Plant these in the spring. Takes 13 days to mature.
Overview
Rhubarb Seeds are a type of seed that grow into 
Rhubarb Seeds can be purchased at the Oasis and occasionally from the Traveling Cart. They can also be obtained from the 

Because the seeds are tied to one of the more profitable crops in the game, they are useful whenever a player wants to turn seed purchases or seed production into a reliable source of Rhubarb. A few practical notes:
- The Oasis is the most direct place to buy them.
- The Traveling Cart offers an occasional backup source, but its stock is not guaranteed.
- The Seed Maker can be used to turn existing produce into more seeds, which is helpful if a player already has Rhubarb on hand.
- Treasure rooms in the Skull Cavern can provide a large batch at once, making deep mining runs a possible way to stock up.
- Mixed Seeds on Ginger Island can sometimes lead to Rhubarb growth, giving the crop an additional source of appearance in late-game play.
Since the seeds are themselves the starting point for Rhubarb production, they are most valuable to players who want repeat harvests or who plan to process the crop in bulk. Even when found only in small quantities, they can be worth saving rather than selling immediately, because each packet represents future crop output.
Official description
Plant these in the spring. Takes 13 days to mature.