LONDON, ONT. -- Backyard surveillance video in east London shows a thief hopping a fence, cutting marijuana plants, and within 48 seconds he was gone.

"He's lucky I didn't catch him," joked Mike Nutt who posted the video on Facebook.

It has happened for years during harvest season, but now that cannabis is legal, police are getting more and more calls.

"Last year was the first fall that we recorded our first marijuana theft," says Tanya Calvert, corporate communications officer with the St. Thomas Police Service (STPS).

"We saw a trend begin and again this year we've seen another spike in theft of cannabis plants from backyard private grows."

Pete Young is a master grower who has cultivated cannabis for 25 years. He was the co-founder of Indiva before recently retiring from the professional pot world.

"You are going to see it more and more with technology and people flying drones," says Young.

"It used to be that 50 per cent of the cannabis you put out would go missing. Now that you are seeing 'mom and pop's' growing it in their backyard, the first thing they will do is call the police."

Last week STPS reported an overnight theft on Hiawatha Street, and Monday they announced that four mature plants were stolen on Curtis Street early in the morning.

"Having an open backyard in St. Thomas and being in condensed living conditions in the city can result in a couple of giveaways," says Calvert.

"The odor is usually a giveaway and some of the plants are huge, and some of them are taller than buildings nearby. If potential thief sees one during the day they'll go back at night."

Calvert suggests harvesting the plants early to prevent thieves, as well as using cameras and even staying home more often to ward off potential burglars.

Young shared some of his experiences from more than two decades worth of growing pot.

"I used to tie flowers around it and people from a distance would think it was a rose bush or some other plant not associated with cannabis and leave it alone," says Young.

"If you are in the city you can put them in dry pots and bring them inside at night. If you want them in the ground you can use cameras or chain-link fencing similar to a dog run. Don't do anything stupid like booby traps, but do anything you can to deter thieves and make them want to move onto the next yard."