[m1ckz]

so far ive lost 50ish to white rot...another 50 left   but  im  losing a few every day now   ,, probably be getting ours from supermarket this year

[Ivor Backache]

I lost a third during my first year and four years later I am almost clear.
1. Stick to the same bed-you can grow onions in this way for several years.
2. Remove a cubic spade of soil at the infected plant and replace with compost and mark with a stick.
3. Don't use your own compost, you are probably recycling the spores. I get horse manure and keep it separate.
4. Plant next years crop about 9" apart, to stop the spores travelling from root system to the next plant.

The sticks might indicate a pattern for the spores, but they will remind you the next year where the infection was.
Stick with it and you will get  better crops over the years.

This year I would consider transplanting some of the onions to break up the chain of infection, especially if you have them closer than 6"

[m1ckz]

interesting  thanx

[LotuSeed]

Can you salvage the remaining ones by pulling them, chopping them up and freezing them?

[mumofstig]

I do that with the ones that get loose, rather than waste the whole onion, just because the bottom has white mould 

[m1ckz]

yes,,,im going to full a few today an try that  ty all

[Alifink]

The sticks might indicate a pattern for the spores, but they will remind you the next year where the infection was.
Stick with it and you will get  better crops over the years.

Can you plant a set in the area you dug out and replaced due to infection or should a gap be left?

[crh75]

I think the idea is you plant an onion in that space the next year, but it is marked so you can keep a closer eye on it in case you did not remove all the infected soil.

There is an onion called Golden Bear which claims resistance to white rot but I have no idea how good the resistance (if any) is!

[Ivor Backache]

The sticks might indicate a pattern for the spores, but they will remind you the next year where the infection was.
Stick with it and you will get  better crops over the years.

Can you plant a set in the area you dug out and replaced due to infection or should a gap be left?

Yes you can. You will have removed all the affected soil and replaced it with clean soil, which in my case will be horse manure. Later this year I will dig over the bed using the horse manure. I don't use my ordinary compost in case I re-infect the soil. The bed is 6' wide so I don't need to walk on the soil.  Cleanliness is so important.

This year I have shallots, garlic autumn/main crop onions, all about 9" apart and so far (touchwood) no sign of white rot. If that remains the case then I can go back to 6" spacing.