Our garlic has all been picked at the allotment this week. It may be slightly early by a week or two but the leaves were starting to go yellow which is usually the first hint that they're ready to be picked. Also, some bulbs were showing signs of the dreaded white rot so I wanted to get them out of the ground as soon as possible. If any of your healthy garlic or onions suddenly keel over the chances are this is what the problem is. The other tell tale signs are stunted growth and a nasty, white, fluffy mould on the bulb and roots when you pick them.
One of the main problems with white rot is that it may be present in the bulbs that aren't exhibiting any symptoms. This will cause them to rot in storage which is a real pest in a plant that we mainly grow to store over the winter months. Another thing that makes it tricky to deal with is that once it's in the soil it's virtually impossible to get rid of. The best estimates I've seen in books is not to plant alliums for seven years. The worst estimate? 20 years! This kind of soil infestation can be a real problem when veg is grown year after year, like on allotments. Especially when people don't rotate their crops!
I only have a 4 year rotation on my allotment which does stop it becoming totally rampant but I don't have enough space, or the impetus, to stop growing in the infected areas - I love fresh garlic! So I take the risk every year and this time the weather has been on my side and it hasn't affected the crop too badly.