2.18.1 Growing thyme
From: skifast123.aol.com (SkiFast123)
Transplanting thyme: a suggestion made by Adelma Grenier Simmons (of Caprilands, CT fame) in one of her many herb pamphlets is to bury one-half of the plant along with the roots in the soil. In other words, you will only, after transplanting, be able to see 1/2 of the plant that you had formerly. The other 1/2 will be underground.
Since thyme is tricky to transplant because its roots are so fine and in my experience easy to sever from the main plant, this method has worked with good results for me.