Well, when I plant my herbs, I just amend the soil with compost then don't really fertilize much... most culinary herbs don't like it...in fact, they will have a stronger flavor when NOT fertilized. but that is just my humble opinion...

I agree with Heathen. I don't fertilise my herbs at all, except with the occasional dose of compost. You'll get better flavour if they're grown in poor soil. I find that most herbs also develop a better flavour when exposed to as much sun as they can get. This applies mainly to the Mediterranean herbs such as lavender, rosemary, sage, thyme, basil etc. Exposure to the sun and heat encourages the formation of the essential oils which give the plants their distinctive smell and flavour.