Warum sind meine Frühlingszwiebeln pudrig?

Mildew.

What you’re seeing is mycelium. The bedding for fungus to grow

It does depends on what kind it is of whether it’s ok to eat or not, but I’d say it’s not worth the risk

If you have other plants, you need to keep them away. It spreads rapidly

Clean everything with bicarbonate powder, heat treat pots and tools.

Honestly I’ve seen a lot of posts where people just wash it off but it’s up to you.

i powdered them