Add lemon juice and sugar to the green tea kombucha and stir until the sugar dissolves.
Using a funnel, fill the flip-top bottles with the kombucha.
Add the sprigs of thyme to the bottles, dividing it evenly among them.
Seal the bottles and let sit in a cool, dark place for 3-7 days.
After 3 days check one of the bottles and if it's bubbly put it in the fridge. Serve cold.
If it's not bubbly, leave it out for a few more days. Check each day until it is carbonated. Once it's to your liking put it in the fridge and serve cold.