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Onion White Rot on Garlic?

I planted some garlic at the beginning of November, but I noticed last week that the containers I'd planted up weren't draining properly. I always put a layer of stones at the bottom of pots when I'm planting something, and the compost is decent stuff, but I think the pots were too shallow. Anyway, this is my first time growing garlic, but I knew it wasn't going to survive living in a swimming pool. I emptied the pots today (I've planted new cloves in much bigger pots, with more stones at the bottom). Most of the cloves looked like they'd not liked their prolonged swim, but one came out with a blue growth on it. I've been looking online, and I'm wondering if this is onion white rot. I've thrown it away, along with the compost, but I want to know what this blue stuff is so that, if it is a disease, I will recognise it in future. image



  • pbffpbff Posts: 433

    Bulbs are prone to getting a blue mould in store and when they are planted, the mould can continue to grow. 

    Hyacinth bulbs are often affected in a similar way.

    I'd say that the water-logged conditions caused the mould to thrive.

    Doesn't look like Onion White Rot to me.

  • Onion white rot (affects all alliums) is usually at the base and rots off the roots, it is usually thought that the fungal spores  are not active in cold weather which is why many of us plant Onions & garlic in the winter. If there was no garden soil in the mix then it is unlikely that it would be in pots. We suffer a lot with white rot on our allotments & I often plant in compost in modules to get plants off to a good start. I agree with pbff diagnosis

    AB Still learning

  • Thank you pbff and Iain R, that is such a relief. image 

    There was no garden soil in the pots. And that's a good tip for me - compost in modules -  as we've put ourselves down for an allotment and, after reading about onion white rot, I have been worrying about the possibility of it running rampant all over the place there (apparently we've got about eighteen more months to wait, fingers crossed).

  • Good luck for the Allotment. Not all sites have it and not all plots on a given site either. Many plots on our site do suffer (including my main plot) but some have escaped. If your site does suffer then  1)use the longest rotation period you can manage, 2) make a strong garlic solution (a whole bulb from the supermarket crushed in about a pint of water leave 24 hrs strain into watering can and then dilute to use.  The theory is if you water the ground about 2-3 weeks before you plant the crop, the spores germinate in response to the allicin compounds but then with nothing to feed on they die out. Then plant out your pot or module raised plants. It's not completely effective but you usually get a reasonable crop.

    AB Still learning

  • Thank you, Iain R image

    Hopefully, fingers crossed (and everything else for that matter), our plot won't have it. But if it does, I will definitely use the garlic solution and grow the plants in pots or modules first. I am a bit obsessive about crop rotation, so I will definitely be adhering to a strict regime and using the longest rotation periods possible. 

    Many thanks again. image

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