The 5-1-1 should be fine. Thyme will grow in ordinary well drained garden soil so a reasonably fast draining 5-1-1 mix should work equally well. And it does for me...I have thyme both planted inground and in containers using that mix.

I successfully grew thyme from seed last year in bad peat-dust type soil. I think 511 would be a luxury for it.

Ok great then 5-1-1 it is then.

I agree with all above, but I've found that a top layer of pea gravel really helps with thyme. Read it somewhere and it works for me.

Thanks. How about something as big as a pond pebble? To keep the rodents from digging into the pots.

What does the pea gravel do?

Possibly help prevent disease to the lower trunk area and leaves?

I seem to remember that it has something to do with: reflected light; and keeping the upper plant dry and clean from soil; and they like their feet cool and their uppers warm/hot.