Responding in the Gardeners' Question Time section, Anne Swithinbank identified it as hemp and pointed out it is illegal to grow cannabis at home. She advised Barry to destroy it immediately – but warned against burning it.
Her answer read: "It looks like hemp (Cannabis sativa). It is, of course, illegal to grow and probably germinated from bird seed. Although it has obviously thrived in the warm summer, you had better destroy it. It is safe to put on the compost heap but I would advise against a bonfire."
Barry Thorp sent in an image asking for identification of a mysterious plant in his garden and was immediately warned to destroy it as soon as possible. According to The Telegraph, the September 2019 issue of the magazine contains an email from Barry who sent a picture of the plant and asked: "Can you identify this mystery plant from my garden?".
Guy Barter, RHS Chief Horticulturist, told The Telegraph: "Yes, this is a Cannabis sativa plant. It is illegal to possess/cultivate it in the UK without a special licence. Some legal cultivation is allowed under licence both for pharmaceutical use and, using low cannaboid content cultivars, for seed, oil and fibre.
Cannabis can germinate from bird seed. It is illegal to grow (Brian Shamblen / publicdomainpictures.net; Kevin Casper / flickr.com).
Wild bird seed can cause illegal cannabis plants to grow in your garden, a BBC Gardeners' World expert has warned readers of the programme's magazine.
"Denatured hemp seed is offered for bird food and viable hemp seed an occasional contaminant and may well have spread via this route. Plants should be destroyed to avoid potential prosecution."
BBC Radio Devon's gardening expert, Sarah Chesters, said: "I think the seed of this came from the bird feeder which hangs just above their door.
"It's quite common for bird seed to contain a huge variety of plant seed and cannabis has been known to come up from it."
Mrs Hewitson said: "I sent a picture in via email and I got a couple of interesting emails back, including one from the police.
Sgt Ryan Canning, from Devon and Cornwall Police, said: "If you come into possession of an illegal drug such as cannabis, you must either destroy it or take it to a police officer.
"We've been told we have to cut it up and either compost it, take it to the police station or take it up to the local recycling centre," Mrs Hewitson said.
After discovering it was an illegal cannabis plant the police were involved.
Patricia Hewitson, from Exmouth, contacted BBC Radio Devon's gardening programme asking for help identifying "a weed".
The microwave method
So although your intentions were good in filling that bird seeder for the different birds in your neighbourhood, your carefully planted cannabis plants have perhaps been compromised by the cannabis seeds in the bird food. The cannabis seeds are not the only seeds that will sprout from the birds discarded the seeds while eating. Some of the seeds that grow from the wild bird seed can produce a hemp plant.
So, although everything in nature deserves to grow just like the weed plant, perhaps providing food for the birds needs to be done with sterilized bird food.
Growing Marijuana- Tips and tricks to maintain a healthy plant
Remove the seed from the oven, and then let them cool before you store in a dry airtight glass jar.
Next time you buy your birdseed, check on the types of ingredients that make up that premium bag of feed. A favourite seed of many birds is the hemp seed. Although not a seed, it is a nut. It’s high in fat content, which is why this seed is extremely attractive to the bird’s taste palate. Birdseed producers add to the seed mix. Non-viable heat-treated hemp seed is inserted into the birdseed mix. The issue is that not all of the seeds get the full treatment to deactivate them.
Male plants will adversely affect the four female plants you have carefully grown. The male plant pollinates the female plant and thus results in the abundance of seeds, which turns your plant into a hermaphrodite. Your wild bird food is perhaps not a good thing for the cannabis farmer.
How to prevent your bird seed from sprouting