Thieves stole £400 worth of stock from Dovercourt DIY store in Kingsway, Essex, after breaking into the backyard.
Co-owner Matthew Stace said in the 18-months the store had been open this was the first successful theft after two failed attempts to break into the shop.
On this occasion the thieves got away with several fence panels and 400 garden canes.
He told diyweek.net: "We weren't too surprised the break-in happened. Other shops in the area have been targeted. If someone wants to get in there isn't a lot you can do about it.
"On top of the bolts and padlocks we were using on the gate, we have now taken further preventative measures at added cost to the business to make the backyard more secure. We have put barbed wire around the top of the walls and painted the panels with anti-climb paint.
"It's just something that as a business we have to recover from. We are just thankful they didn't get into the shop as the cost to us would have been even higher."