[Paul 26b]

Hi, I bought some red onion sets and decided to start some off in modules of general purpose compost.  They are in an unheated greenhouse.  They all seen to be rooting well as have all the yellow onions but today I noticed a few of the red ones have a white fine mouldy substance on them, from the compost level up to the middle of the set.  Any ideas what this is and how I should proceed please?

[m1ckz]

not sure   but white rot comes to mind

[Trikidiki]

White rot normally affects the basal plate first.

I'd suspect it is botrytis growing on the dead skin of the onion. Likely a bit damp. I've had it before and just wiped it off and they went on to grow normally.

I gently rub off the loose dry skin from the sets before planting now.

[Paul 26b]

not sure   but white rot comes to mind

Oh dear, I hope not

[Paul 26b]

White rot normally affects the basal plate first.

I'd suspect it is botrytis growing on the dead skin of the onion. Likely a bit damp. I've had it before and just wiped it off and they went on to grow normally.

I gently rub off the loose dry skin from the sets before planting now.

That does sound more like what I have, hopefully not just wishful thinking, many thanks.

[JimB]

.

Never have had much luck or crop from the reds, even heat treated ones!

Give them a spray with fungicide and put them in a well ventilated position which may save them to some extent!

[Trikidiki]

I think Marshall's are the only ones who do 'heat-treated' sets by mail order. Bought from them a few years back and they all bolted within weeks. I rang to complain and when they checked the order they had sent me non-heat-treated as they had run out of heat-treated, without telling me. I told them I wouldn't buy from them again, so now grow reds from seed.

[wrinkly1]

i also had all my red sets go to seed. 2 years running. so its seed for me now

[Paul 26b]

Oh Dear, sounds like the red sets were a bad idea, Ah well live and learn.  If i get some seed this week and start them off in the cold greenhouse, will that be ok?

[Trikidiki]

I would wait a while and plant them straight outside.

Stress can trigger them to bolt and then transplanting may stress them. Try to keep the watering uniform as a dry spell followed by a deluge wil trigger it as well so water during any dry spells (as if!).