Rare Seed is an item that, when planted in the fall, grows into a Sweet Gem Berry after 24 days. This berry can be sold at a high price or given as a gift, and is also used in a secret quest where it can be traded for a unique item. The seed can be purchased from the traveling cart and is considered a valuable addition to a player's crop collection due to its rarity and profitability.
The item ID for Rare Seed is 347
This ID will work on PC/Mac (Steam), PS4, PS5, XBOX One, and Nintendo Switch.
Spawning items in Stardew Valley is a little unsual and is not done with commands. You will need to utilize what is called a cheat to set your character's or animal name to the item id. To do this you cannot use just the item id, you will need to surround the item id with brackets. Ex. [347]
Spawning Using the Animal MethodTo spawn Rare Seed while using an animal, you will need to head over to Marine's Ranch and purchase an animal. Once you have have an animal chosen, name the animal with the item id with brackets like this [347] and you will receive the Rare Seed item. This method can be done using an existing character and is convenient but will cost some gold every time you want an item.
Spawning Using the Character MethodTo spawn Rare Seed while using a character, you will need to create a new character and name it with the item id with brackets like this [347]. You will then receive the Rare Seed item when you speak to a villager. This method is easy and free but cannot be performed on an existing character and you will be stuck with that name unless its edited.