In a pot, stir together three cups of water, the sugar, the lavender and cardamom pods. Bring to a boil over medium-high heat. Once the sugar has dissolved, remove from the heat and cover the pot with a lid. Allow to steep for 10-15 minutes. Strain and allow to cool completely.
In a large pitcher, combine the lemon juice, the remaining water and two cups of the simple syrup. Stir and test. Add more sugar to sweeten to your preference. Refrigerate until ready to serve. Pour over ice and enjoy.
Notes
This simple syrup can be made a few days in advanced and can be used in any other recipe that calls for simple syrup.