Personally I would dig the sprouts which should come up as individuals and reset them in a revitalized and refertilized bed about 6" apart. That should give you the best size possible; other wise next summer all you will get is very likely only dinks for size. Mulch and water them in. Only rewater when the ground layer under the mulch goes dry. You may also have sprouting bulbils, if what you planted last year was a hardneck variety. Those will be much smaller and should probably be bedded out by themselves to grow on an extra year. That means there may well be two distinct shoot sizes that can probably be sorted out from each other.

I concur with OldDutch, it would be best to carefully separate the individual plants & transplant them at proper spacing. I've done this in Spring with my walking onions, but never with garlic... the walking onions were very healthy after transplanting. Personally, I would allow the plants to develop a couple leaves before transplanting them; but I confess that I don't know what stage of growth would best recover from transplanting.

Garlic can be transplanted any time they start to show top growth in the spring and the ground is frost free. The sooner the better, too, for the longest growing season and the biggest resultant bulbs. If the ground is thawed, it is definitely warm enough. The individual shoots are easy to separate since the cloves fell apart the preceding autumn.

I always plant my garlic in the fall, usually October for me here in Virginia, though I've done it earlier. Of course, my garlic stays in the ground over the winter. Garlic just doesn't seem like something you can expect to plant in the spring and get really great heads by the time it dies back in early summer. At the same time, I often have heads or cloves missed at harvest time that I find newly sprouted at some time from fall to spring, and I gently dig these up and break them apart to space the individual plants 4 to 6 inches apart. I've gotten good heads of garlic from these divisions, though the absolute best are the fall planted cloves. So I would definitely dig and divide your sprouting heads into individual plants as early as possible when the soil can be worked. And realize that garlic is not usually a fall harvest kind of crop - they should be harvested when the tops die back when temperatures and day length cause the tops to die back.

Thanks all. I am in the process of digging up and replanting separated clove-starts. It is not as easy as digging/drying summer/fall than replanting these starts but those I already did seem to be doing well - but more to do. Thanks for your advice!

First I am in South Carolina, so my winters are lighter/warmer then some.

I plant single cloves six inches apart in Oct. then harvest in June/July the next year.

I still haven't dug the all up yet but the transplants on about 60 look 100%

Good for you. Good luck with the rest. BTW garlic scallions can be quite the treat and if you end up with more than you need to divide, you just leave the rest in the ground and harvest the scallions as you need them.

I missed some underdeveloped onions & garlic in the garden last year and they came up again in the spring. (Zone 6a) I want to replant the green garlic for bulbs. (even if they end up being puny)

I had to wait several weeks after I dug them up and divided before I could replant In the garden. I set them in a dry location outside for a couple of weeks so they wouldn’t turn to mush—the way you would start curing onions.

They had quite a bit of green growth and and some brown leaves as well. I trimmed it back a bit, but now I’m worried that might have been a mistake. Will these continue to grow if I plant them? should I let them “cure“ a while longer before planting? Thanks in advance!

I wouldn't have "cured" them at all but would have replanted them right away.