Allotments 4 All

planted my onion sets in small pots of composts last week. have definitely not overwatered but just noticed that some of them have white mould growing  around their base.
Was I wrong to do this? I thought i saw it on a TV gardening programme. We live in the frozen NE of England so was starting them off indoors.

Ohh..good thing that you did start them in pots...DO NOT plant in ground until you know what it is. If it is the dreaded white rot..then those will have to be destroyed as you DO NOT want that in your soil...but it could well be just the outer layers that are starting naturally decay. So no panic yet. If the onions stay alive and don't go soft and die..then it is natural..but if the 'rot' progress and affected onions start wither and look unhappy..get rid..burn or bag and bin em...but what ever you do, don't get the affected compost anywhere near your compost bins or  discard on to soil.
Just keep eye on the situation now.. :)

Absolutely good advice. Follow exactly!

Thankyou. Should I take off the mouldy layers to investigate further then?

Yes -even if you waste one it's worth it to know if it's white rot. I had same thing yesterday BTW with two garlic bulbs :(

I've just noticed that it's only the red onions which have got this.
Should i wait to see if they sprout though before doing anything - and if they do sprout does this that it isn't onion rot?

Am not sure what I am supposed to be looking for to confirm it. What else could it be? Will try and take a photo and upload it later.

here it is...when I uprooted one from the compost I noticed that it white roots so it has made roots already. H linkope this pic opens..not quite sure what I'm doing with tinypics

oh well that didn't work then   :-\

http://tinypic.com/edit.php?pic=67phcw&s=7

In my experience white rot is generally found on the roots and is not usually visable like that - it has only ever affected me towards the end of a season as well.
Do those little pots have drainage holes?  It looks very wet to me and onions are not a fan of really wet conditions.  It seems to me that they are just rotting in the pots but either way I wouldnt be that hopeful!

the pic was taken just after I had watered so I guess that's why it may look wet. The little pots do have drainage holes. That's the first time I'd watered since inserting them intheir compost a week or so ago and so i don't think it's cause they're too wet. The compost was bone dry until this am when I decided to water - can you have dry onion rot?

White rot is usually in the soil and becomes most active when the soil temperature is about 15C, ie in early Summer, so unlikely to be in your compost which looks to be peat based.

Hi Spudcounter,

It certainly looks like white rot. You say you started them inside, is this in your house or in the greenhouse, I once had this trouble, fortunately it was not the dreaded white rot but the fact that the temperatures in my cold greenhouse were so extreme ie:- 85deg in the middle of the afternoon and 2deg at night I probably watered too much so they just rotted. I now plant outside where they are to grow in the first week in April with fleece over them until they start to sprout.  I have never had the rotting since. In fact I am still eating last years onions

yes they are in peat based compost, not soil. Is not white rot in the actual bulb itself to start off with then?

They have been started off in my house. To be more specific in my daughter's bedroom which is an attic conversion and can get quite warm in the day, but it isn't humid. The compost was bone dry until I watered it yesterday.

The white rot infected allium bulb produces thousands of "sclerotia", which look like very small black seeds. These remain in the soil for a few years until the "sclerotia" sense the presence of allium roots   close by. The "sclerotia" then germinate and attach themselves to the allium roots and infect them.
So white rot is usually lying dormant in the soil. It could be on the bulb, though I would have thought that the bulb would be rotten and you would not plant it.

That does look more like a storage rot to me..... just a mouldy bulb...

well I guess if it is a mouldy bulb I could try and carefully wipe those affected and see if they recover,. They have produced roots now and so are growing and presumably taking in what they need from the compost. I shall sacrifice one and cut it in half to determine how far the mould has gone into it.