1 teaspoon
1 teaspoon ground = 1 tablespoon fresh. Ground or dried herbs are actually stronger than their fresh counterparts.
One small sprig of rosemary converts to 1/2 a teaspoon of dried rosemary.
One fresh bunch of thyme is roughly equivalent to one teaspoon of dried thyme.
With thyme one fresh sprig equals one-half teaspoon of dried thyme. In general, use two to three times the amount of fresh thyme as dried. When adding to soups and stews, crush the leaves between your hands before stirring it in your recipe.
Dried thyme has a very strong flavor. Measure in 1/4 to 1/2 teaspoons depending on the volume of the ingredients.
one and a half to two
How big a sprig? You must be specific. But 1/2 tsp dry ground thyme = 1 tsp fresh thyme if that is any help. That's the leaves not including the stem.
Dried herbs are normally twice as strong as fresh, so 1/2 a tsp.
How much ground thyme do I use in place of chopped thyme
You can't really measure it that way, despite what the books say, which I very much refute on. It's said that 1 tsp of ground thyme is equivalent to 2 and half tablespoon of fresh thyme. But it changes when you blanch your fresh thyme first - That's when they are activated. Their smell goes stronger, their 'stem' bursts out in flavor and everything in the herb goes wild. Same goes to other strong herbs like dill, rosemary, etc.
A 3-4 inch sprig of thyme will produce a tablespoon, however, a dried sprig of the same length will produce barely a teaspoon.
If you mean dry thyme for fresh thyme, then plan for 1/3 as much dry as fresh. If the recipe calls for 3 tsp of fresh thyme, use 1 tsp of dry.