[brittanyjohn]

I harvested my Onions yesterday and out of 200 about 25 had the dreaded white Rot. i have read up on the subject and seems i cant grow onions / Garlic / leaks in the ground for 7 - 10 years  .
Has anyone else had this problem and what else could i grow in the contaminated ground ?.
The uninfected Onions are fantastic though and a few at around 5lb.

[Kleftiwallah]

Good morning brittanyjohn,
congratulations on a crackin' showing of onions.  We have the dreaded  onion white rot in our ground, we grew a crop in a raised bed with imported soil and got a good result.  We grow an occasional onion just to see if our ground is clear but no luck so far.  Cheers,  Tony.

[Aunt Sally]

Try the garlic trick.

In early August in the UK, (could be later where you are) water the ground where you want to grow your onions next year with a solution of crushed garlic cloves in water. Make it quite strong, I have used about 6-8 cloves in a watering can.  It won’t affect any plants you’re growing there this year.

The white rot spores in the ground will detect the garlic smell and germinate and grow to find the onions.  But as there are no onions they die.  It’s not a perfect remedy but it reduces the problem greatly.

[Growster...]

Although I don't grow onions any more, Aunty, that sounds like a real plan! Fabulous!

I used to grow those Marshalls monsters, but even four of us couldn't use up one whole one...

[brittanyjohn]

many thanks all for the advice and answers 

[Aunt Sally]

You’re welcome. Fabulous onions by the way, John.

[Blewit]

We use garlic powder applied as soon as the garlic and onion crops are lifted and grow in the same beds every year. If a bulb shows signs of infection it's lifted before the white rot can set seed. Working like this white rot infection has been reduced in the allium beds from 100% to just 5% in five years.
Golden Bear onions (grown from seed) are marketed as resistant to powdery mildew but are also very resistant  to white rot. We've even had mildly infected GB bulbs that have still stored well.

PS can't rotate the allium crops as the whole allotment is infected with white rot.