Two fire crews dealt with a wildfire half the size of a football pitch at the Fontaine Vinery.
Firefighters were called to the large Fontaine Vinery site just after 6pm on Tuesday (4 August).
A plume of smoke could be seen drifting out to sea after this, and the Fire Service advised neighbours to close their windows.
The area alight was roughly 60m by 60m, or half the size of a football pitch.
Part of the old vinery has been in light industrial use for some years but it is understood no buildings were affected.
It is though in a built-up area and, though it took two hours to extinguish, it is understood crews remained on scene given the undergrowth is so dry.
Fire crews used a drone given to them by Guernsey Ports to assess the extent of the blaze.
Part of the site in St Sampsons is due to be turned into affordable housing, although it is unclear which part was burnt.

Guernsey experiences hottest July on record
Thousands expected to attend CI Pride at Guernsey's Bathing Pools
Change to how CI weather warnings are issued
Guernsey Water urges sensible use but not a hosepipe ban
Guernsey Prison staff continue their work to rule
Merrien bags silver for Guernsey in Glasgow
Guernsey Scarecrow Festival raises bumper amount
States reject idea to install parent-child parking around Guernsey