Short of an infestation of some kind there's no reason to rotate.

In fact, 19th century onion breeders discovered that alliums actually do better when grown in the same beds year after year.

My alliums beds are in their sixth year. And Martin has some that, if I recall correctly, have been used continuously for 20 years.

I believe I might have nematodes in mine. I had tomato root knot nematodes in the same bed; if these are nematodes at all, I am assuming they are different. (see my post;" what's happening to my garlic")

Good to know I can replant my garlic in my one raised bed I built last year. Of course I plan to add to the soil afetr harvest and before planting.

Aside from the compost, what else can I add to help improve the soil for garlic? I may have a source for some 5year old horse manure and buckets of coffee grounds. Are these good for garlic?

yup.

You want garlic to grow nice, large leaves early in the season to grab all the sun energy they can. After that you want them to have ample phosphorus for bulb development, but you also want them to have a complete buffet of major and minor nutrients as well as a host of beneficial soil organisms and enzymes. That is where the compost comes in.

Manure and coffee grounds will add mostly N, but also a small amount of the same stuff compost does. After all, they become compost soon enough. They are both great food for the soil.

Equal part of bone meal, blood meal, and wood ashes, along with compost, are all I use.

The amendments are worked into the soil, before planting, at the rate of once up of each per ten row feet of garlic. Then, in May, the plants get side-dressed with the same mixture, at the same application rate.

This seems to be the balanced diet they require.

I plant my garlic in a raised bed in mid October, before frost gets into the garden. I cover the garlic with three bags of organic chicken manure in February. The garlic is supposed to be dormant during the winter. If you put manure on the garlic in the fall the garlic will start to grow during the winter season when it should be dormant.