Red wing is a very long day onion. They need the summer solstice to trigger bulbing. They should be getting on with it NOW for harvest in September. They have (as do all onions) high demand for water and nitrogen.

Thank you farmerdill. I have been watching them for signs of bulbing, hopefully I will seem something happening soon.

None of my spring seed-sown onions will form bulbs until well into July. In the cycle of things, I just get the garlic cured and ready to move to storage and it's time to do the same with the summer onions.