Fire crews were called out at around 10.30pm following reports of a blaze in Ceres Court, Sittingbourne.
The garden fence was alight and the fire caused heavy smoke logging to two of the maisonettes and damage to both downstairs bathroom windows.
A man suffered from smoke inhalation as a result.
Emergency crews say the fire appears to have been started when a discarded cigarette sparked a blaze amid rubbish stored next to the fence.
Sittingbourne crew manager, Kevin Ford, said: “Fires like this have the potential of becoming much larger and we would urge people to think carefully about where they store rubbish, particularly over Christmas.
“Luckily, it was detected early and extinguished swiftly by fire crews but could even have been life threatening had it spread into the homes.”
Fire crews are particularly keen to get the message about the safe storage of rubbish out in the run-up to Christmas.
They urge householders not to allow rubbish to block escape routes, not to store rubbish by doors or windows, and don’t store bins or sacks against your home or too close to sheds or fences to prevent fire from spreading to other buildings.
They also remind smokers to carefully discard cigarettes and ensure the contents of ashtrays are cold before putting them in a bin.