No, it has nothing to do with the fact that each bulb has one stem and just a single row of cloves. That’s typical of hardneck garlic, the more expensive form of this cancer-fighting vegetable. The more common softneck garlics come without stubs and have several concentric rows of cloves, protected by lots of papery skin.
What’s wrong is the way I’m storing garlic—exposed to light and heat. (That’s a window in the background.)
You should wrap the heads in netting (sort of like shower caps for garlic heads?) or throw them into a paper bag, kept open somewhat to allow the air to circulate. Or buy a fancy garlic pot with side holes for ventilation and a lid to block light. Or better yet, keep garlic in the fridge, she says, on a shelf, not in the crisper drawer. The drawer is simply too humid and will cause the garlic to sprout.
Under the right conditions, your friendly bunch of anti-cancer garlic should last up to a couple of months.