Patrols are being stepped up by police in Thorne, Doncaster, after a spate of shed break-ins.
Officers are concerned that householders do not give adequate protection to the valuable items in their outbuildings.
Sheds can easily contain more than £1,000 of gear which is more vulnerable because of the structure of the buildings.
In the past week there has been a blitz on sheds in Thorne, with three targeted in one night on Wednesday into Thursday.
Raiders got into a shed in Brooke Street by removing the door hinges and got away with £500 of power tools, a £400 lawnmower, and a strimmer which was valued at £80.
Another lawnmower, worth £200, was taken from a shed in Foster Road after the lock was forced.
And the padlock of a shed in Millcroft Close was forced in the night so the thieves could steal a mountain bike valued at £400.
Supt Eddie Murphy, of Doncaster police, said: “People need to ask themselves, ‘Do I know the value of the property in my shed?’. Because it adds up to more than people think.
“Fishing tackle can cost thousands of pounds and yet be stored in a shed with just a lock and where the hinges can easily be unscrewed.
“I would advise people to consider a separate burglar alarm for the shed, or have it linked remotely to the house alarm.”
Supt Murphy said the increase in such offences across Thorne had prompted extra patrols at night.
n Thieves entered the compound of the Stratstone Land Rover dealership in Wheatley Hall Road, Doncaster, and stole £2,000 of headlamps from three used Range Rovers on Thursday evening.