Just about any herb you can grow will dry well in the oven. Clip herbs for drying before they flower and early in the morning right after the dew is off. The exception is dill, which should be harvested after the seeds have developed. Oven drying is best begun early in the day.
Harvest the herbs when mature but before they’ve begun to flower, as the flowering takes strength from the leaves. The most potent leaves are found at the ends of the stems, and they decrease in strength as you get closer to the stem.
Throw away any discolored or dead leaves. Remove the leaves from the stems and place in a single layer on each tray and place each tray on an oven rack. Be sure there’s room for the air to circulate around each leaf. Place the racks in the oven.
Prop the oven door open so that the air can circulate, but keep an eye on the thermometer so that the temperature remains between 140°F and 160°F. (You can speed up the process a bit if you have a small electric fan to set up so that the stream of air blows into the oven.)
Once you’ve got everything nicely settled, set the timer for 30 minutes.
When the timer buzzes, rotate the racks. Move each rack down one space and put the bottom rack on the top. Reset the timer. Each time you check you repeat this process so that every rack will have equal time. This will correct for any temperature differences inside the oven. You can also take this opportunity to turn the food over so it dries more evenly.
Repeat step 4 until the herbs are completely dried, about 2 to 4 hours (times vary depending on the herb).
info idiotsguides.com,pics mine