[rhysdad]

I'd planted some Japanese overwintered onions in late November last year where they sat doing very little (understandably) over the winter months. This past few weeks milder weather have really set them off though, and, after having a furtle, the bulbs themselves seem very emaciated. There is good top (stalk) growth, growing about 8" this last month,  but the bulbs themselves seem very feeble. I dug in some Growmore when planting and have chucked on a bit of pelleted chicken manure (as per John's advice on here) but would some Fish, Blood and Bone help? (not that'd it do much harm  )

[Aunt Sally]

You've probably given them enough food for now.

It's very early spring, they've got quite a long time left to grow and fatten up.

[viettaclark]

As Mum says, they won't be ready to harvest til July/August so let them be and feed again in 6/8 weeks. Make sure they're watered!!

[JohnB47]

I posted a similar question last spring and yours is just one of a few that have appeared recently. Perhaps there should be a sticky for this.

The answer is that the bulbs disappear over the winter, probably as the plant uses the food supply in them. Don't worry, there's almost certainly nothing wrong if you've got good growth above ground - they'll soon fatten up.