Dean, who lives in Mickley, offers tips on gardening and sets his followers fun tasks, not least the world's first washing basket challenge!
He said: "You get a flexible washing basket which can hold 60 plants and you transform it into one of the most beautiful displays you'll ever see.
"In our group it's a competition but there are no winners and losers because anybody who is going to attempt it is a winner in my eyes....I want everyone to think they can do it. Each week I give them guidance. We sowed the seeds in March and we're in the process of moving them into trays to be ready for the third weekend in May when it's guaranteed to be frost-free."
His washing basket challenge inspires thousands of attempts every year, not all of them submitted for the friendly competition.
The challenges don't end there. Last year Dean spurred members to grow potatoes in a 30-litre bucket, this year it's root vegetables in a wellie boot or blooms in a bag.
Another of his challenges is growing herbs from seeds, then picking five of them to use in cooking a meal.
The Facebook site, which he co-owns with Michelle Lees, is much more than a gardening forum. It's a place where people can share their personal or work problems and where online Q & A sessions are held once a week for 20 members. Dean said: "It's like being out on a Friday night with your friends around a big table and just talking about putting the world to rights." On one occasion, he spent an extra two hours after the meeting ended chatting to a widow who was tearful and lonely.
When he lost his mum last year, Dean, 55, said he was overwhelmed with the messages of support that came through the site. "It pulled me through a bad time, through the grief and the selling of the house which was my childhood home," he said. "I even had people calling me up who were willing to help me for free in the process of selling my mum's house."
Dean's grandparents on his dad's side have had a big influence on his life. He credits his grandad David for inspiring his interest in gardening. "He taught me as a young child how to sow seeds and pot them on."
His grandma, Annie, made whopping Yorkshire puddings and Dean spent 20 years trying to emulate hers before succeeding and sharing his discovery on the Facebook page. He said: "They don't need Aunt Bessie's, now they've got Uncle Deano's!"
Since moving to Tennyson Street with his partner Claire six years ago, Dean has transformed his 250ft-long garden.
He said: "I divided a quarter of it for vegetables, added 14 raised beds, put a greenhouse in and new fencing.
"I grow stuff that I want to eat and I want to be self-sustainable. Last year we were self-sustainable for potatoes and onions. I'm going to try and be successful at growing carrots this year.
"I'm also doing a wall of flowers for the first time down the right hand side of my garden and will try to grow chrysanthemums with big blooms."
His Facebook site grew from an initial blog about his garden three years ago. He said: "Straightaway we had experienced gardeners wanting to help me. It was like a community that I've never experienced before...strangers coming together wanting to help. In the last two years a lot more people have become interested in gardening, it’s therapeutic, gives peace of mind and is an achievement.”
Dean, who has a son and two grandchildren, works as a carer. Claire and he moved to Mickley from Conisborough, near Doncaster, to be near Claire's daughter Bethany and grandsons Logan, 6, and Eli, 5.
As a teenager, Dean was a striker in Bolton Wanderers alongside such team-mates as Sam Allardyce who went on to become England manager, David Cross who later played for the England side and Asa Harford who became a Scottish international.
He moved to Exeter City for a season before transferring to Weymouth where he played from 1987 to 1989.
Following retirement from professional football, Dean worked as an engineer in a job which took him to Canada but six years later returned to his native Conisborough following a divorce. Back in Conisborough, Dean and Claire, who had also divorced after a long marriage, met up again and rekindled a romance that they had had as teenagers.