Question: what is the best temperature to grow onions?
Answer: Onions are adapted to a wide range of temperatures and they are frost tolerant. Leaf, root, and bulb development occurs in cool temperatures between 55° to 75°F. Optimal onion leaf growth occurs at 68° to 77°F (20° to 25°C). Once bulbing has begun onions easily tolerate temperatures higher than 75°F.