I don't know why you would want a root hormone in there.
If that fertilizer is a regular chemical blend, it will not last long in the soil. So using very small applications of it would likely be the way to go. A little bit at planting time and a little bit more during the spring time.
I put some compost combined with an organic fertilizer blend underneath the garlic bulbs at planting time and that's enough to get them happily to harvest time.

I use Bulb Tone at planting time, and a little blood meal (nitrogen) in spring.

In your reading up on garlic, I highly doubt anything you read recommended a fert with that sort of formulation (if you read something like that, you know the source is a poor one). And I too wonder what the reason is for a rooting hormone.

Nonetheless, I fork in manure about three-four weeks before planting. Then I plant, mulch, and in early spring I side dress with blood meal, then from mid spring-early summer a couple-three organic liquid nitrogen fert applications to ensure good top growth.

Dan