Hi SuperSprout.
My Cristo garlic have very thin stems (but gently scraping shows the bulbs to be a good size I believe) and this variety collapsed a few days ago. I "staked" each one with short canes, thinking it was too early for harvesting... The other varieties have much thicker stems (but bulbs no larger!) so are all standing firmly.
However, I have just read that I should lift them as soon as they flop over, so I'll lift them later this week.
mat