Onion is a seed in FarmVille, available after reaching level 34. The seeds cost 170 coins to plant, and can be harvested every twelve hours for 275 coins. They also award 1 XP per plot.
Freshly planted Onion.
Onion at 33% growth.
Onion at 66% growth.
Onion ready to be harvested.
Onion treated with Crop Fertilizer.
Onion after having withered.
*All images © Zynga
Farm Trivia: The Onion was one of the staple foods of the ancient Egyptians, and was believed to represent eternal life.