Four fire engines and 21 firefighters and officers were called to a fire at an allotment in Creighton Avenue, East Finchley.
A range of allotment sheds and surrounding shrubland were destroyed by fire.
The Brigade was called at 0433 and the fire was under control at 0720. Fire crews from Finchley and Hornsey fire stations attended the scene.
The cause of the fire is under investigation.