In a large saucepan over high heat bring water just to a boil. Remove from heat, stir in dried lavender flowers, and let steep for 20 minutes. After 20 minutes, strain mixture into a deep kettle or pot, discarding the lavender flowers. Stir in lemon juice and pectin; continue stirring until the pectin is dissolved.
Over high heat, bring the mixture to a boil then add sugar. When the jelly solution returns to a hard rolling boil, let it boil for 2 to 4 minutes (see below), stirring occasionally.
2 minutes - soft gel.
4 minutes - medium gel.
Testing for "jell" (thickness - I keep a metal tablespoon sitting in a glass of ice water, then take a half spoonful of the mix and let it cool to room temperature on the spoon.
If it thickens up to the consistency I like, then I know the jelly is ready. If not, I mix in a little more pectin (about 1 teaspoon to 1/2 of another package) and bring it to a boil again for 1 minute
After boiling, transfer the jelly into hot sterilized jars. Fill them to within 1/4 inch of the top. Process in a boiling water bath for 10 minutes. Adjust time according to your altitude.