Four fire engines and around 25 firefighters tackled a fire on Woodlands in North Harrow.
A garden shed, two sections of garden fencing and a trampoline were destroyed by fire. There were no reports of any injuries.
The fire was very visible and produced large amounts of smoke. The Brigade's 999 Control Officers received 16 calls about the incident.
Residents were advised to keep their windows and doors closed.
The Brigade was called at 1149 and the fire was under control by 1323. Crews from Wembley, Southall and Hertfordshire Fire & Rescue Service attended the scene.
The cause of the fire is under investigation.