[Lucy Ellis]

Hey all,

A complete newbie to the forum and to growing food. I bought these onion sets from a local garden centre a few weeks back and was told by the seller it was too early to plant out. After watching a few videos on YT I figured I’d get them started in modules in the greenhouse.

These have been in here about two weeks, popped on top of shop bought multi purpose compost.

I noticed this white stuff a couple of days ago and tried to google what it could be and came across onion rot, but from what I understand that disease is usually in the actual soil. Can it be in multi purpose compost too. Are my onion sets ruined?

Any help appreciated.

[Gardener and Rabbit]

Hi Lucy

It's probably some other mould that is simply enjoying cool humid conditions in your greenhouse to grow like that.

I'd increase ventilation if you can, or simply put the trays outside now, since we're in mid-March when a lot of onion sets can be planted directly outside.

G&R

[Kleftiwallah]

Onion white root rot is usually restricted to the root plate.  I know, we have suffered from it for years.  It doesn't look like it to me. I sincerely hope it's not.

Cheers,  Tony.

[AndyRVTR]

It just looks like bog standard mould to me, compost maybe a bit wet.

[Aunt Sally]

White rot strikes at the height of summer,  August where I live.

[Lucy Ellis]

Thank you for your replies.
If it is 'standard mould' is it still Ok to plant out? I have shoved them in the raised bed anyway, so we'll see how they get on, I just didn't want to infect the soil with anything.

Thinking about it though.. I have had a few seedlings die with what seems to be 'damping off' I'm now wondering if it could be related.