Items stolen have included bicycles and power tools.
Sgt Sarah Alvey, of the Tonbridge and Malling community safety unit, said: "With Christmas gifts such as bikes and scooters being stored in garages and sheds, now is the time to be thinking about what security measures you have in place to protect your property.
"Bicycles, power tools and gardening equipment are some of the most common targets but there are a number of steps residents can take to avoid falling prey to opportunist thieves.
"I would also encourage residents to contact their local PCSO to arrange a time for their bike to be security marked and to use measures such as doorbell cameras and CCTV to help secure outbuildings."
Kent Police has issued further advice to help prevent outbuilding thefts:
Use forensic marking kits on possessions. These are traceable liquids which carry a unique forensic code, registered to an address or location. They are known to be deterrent to thieves and can help us identify suspects.
If you have shed or garage alarms ensure they are activated and use close shackle padlocks and install security lights where possible.
Make sure garden gates are closed and locked from the inside and store bins and ladders carefully so they can’t be used as climbing aids.
Disable lawn mowers and other large machinery when not in use and chain items together or to a solid anchor point.
Take photographs and record details such as serial numbers and identifying marks as these can also help to identify items if they get lost or stolen.