Q: If a recipe calls for fresh herbs and I only have dried, or the other way around, what is the substitution?

-- Dave

The general rule of thumb is that one part of a dried herb has about the same strength as three times that amount of the fresh.  If a recipe calls for two tablespoons of fresh sage, for example, then you could substitute one third that amount or two teaspoons of dried sage.

Of course, that is just an approximation, and may not hold true for all cases.  Because dried herbs go stale, the amount required may be more.  On the other hand, for some herbs, the ratio may  be more or less than 1::3.

In practice, it is better to start with a smaller amount, maybe using 1 part in 4 when substituting dried for fresh, and then taste the result and adjust if necessary.  For substituting the other way around, fresh for dried, start with twice the amount and work your way up.  In cooking, it is almost  always easier to add more of something than it is to take away too much.

The problem comes, however, when the recipe doesn't allow you to taste ahead of time.  In that case, you just have to use your best judgment on the flavors involved, and the quality of your ingredients to decide how much is appropriate.  I still would be conservative, as I would rather the dish be slightly under-flavored instead of overpowering it with the taste of the herbs.