Preheat the oven to the lowest temperature (120-170°F is best) and set an oven rack to the middle position.
Spread the herbs and lemon zest on a cookie sheet and place it in on the middle rack in the oven. Let the herbs dry for 2-4 hours in the oven, tossing the mixture every 30 minutes or so.
When the herb mixture feels dry, remove the pan from the oven. Let the herbs cool.
When completely cool and dry, transfer the mixture to a mixing bowl. Crumble the herbs with your fingers and stir in the garlic and sea salt. Transfer mixture to an airtight container or jar.