I think that if you had refrigerated them from January to now, and then plant, they should give you greens in late summer. Another choice for garlic type greens are garlic chives, or garlic grass. As you know these are fairly hardy and peak at flowering stage about mid August. I usually allowed them to drop the seeds where they may and my clumps get bigger over the years. Now, I am removing the seeds and blossoms as I don't want more spreading. Even for that, if the seeds were collected from last summer, they can grow well all summer for this year and can probably be harvested in fall.

I know April would be too early, If spring garlic planters are planting in April for a August harvest of mature plants .
If I plant garlic chives I only harvest leaves I want to harvest the whole plant .

I'm thinking lst of July/lst of August. You will have to experiment a little to zero in for next year.

The answer may be in certain bulbils. Some varieties have large bulbils which will produce a divided bulb even when planted in the spring. Those with smaller bulbils may make only a round despite fall planting. Smallest of all that I've seen, Music, may be the one to experiment with. If they can be tricked into growing shortly after the parent plant is mature, they'd give you a perfect garlic scallion by October. I got almost no growth from them when planted last fall. Suddenly that area is almost solid green spears just over an inch long. However, some were also spilled into the cold frame last fall. With a few weeks earlier start, some of those are at 4 or 5 inches already.

Martin