Dennis Cooksey remembers with great clarity the day he lost his sight. “I woke up, and looked at my radio alarm clock to see what the time was,” he said. “I thought I must have switched it off, because I could not see the red figures. I got out of bed and stubbed my foot on the bedside table, and realised there was something wrong.”

It has been three years since Mr Cooksey went partially blind, a burst blood vessel damaging his one good eye 40 years after a workplace accident had blinded him in his other eye. At 81 he could have been forgiven for accepting his fate.

Mr Cooksey had his carrots to look after, though, not to mention his cabbages and cauliflower, broccoli and onions. Thanks to the charity Thrive, and his own extraordinary efforts, the former steelworks engineer is now as active on his allotment in Rotherham as he ever was.

For one man to find happiness in the simple pleasures of gardening, despite having lost his sight, would be cause enough for celebration, but Mr Cooksey is not alone. Three years ago he set up an allotment gardening group for blind and partially sighted people to grow their own produce with the help of Thrive, one of the charities that will benefit from this year’s Times Christmas Appeal.

One of Thrive’s missions is to help those who have become disabled through an accident or illness to get their life back through gardening. In the group’s polytunnel, on a cold and drizzly winter afternoon, half a dozen members are getting their hands dirty. They are filling loo rolls with compost and using them to sow broad beans under cover before planting them outside in the spring. It is a simple but effective technique and a simple job, but the pleasure it brings is beyond measure.

“It has enabled me to continue gardening,” said John Saunderson, 73, a retired mining engineer who lost his sight to glaucoma two years ago. “We’ve grown as friends, too.”

Janet Bartholomew, 57, has suffered from macular degeneration for 20 years and was registered blind 18 months ago. “If there is Heaven on Earth, it is this allotment,” she said. “I had never done vegetable gardening before. I know a lot more now than I used to. It was something new to me and now I’m reaping the benefit.

“Every time we come here I get to take a bag of goodies home, whatever we’ve been growing — leeks, potatoes, sweet peas. I love sweet peas – they are wonderful.”

She has started pickling her own produce, too. “I do red cabbage and beetroot and onions. It does not sound much, but you would be amazed how much nicer pickled onions are when you have done them yourself.”

The social aspect of the group’s weekly meetings matters as much as any gardening they might do. “I’ve got a new group of friends now,” said Mrs Bartholomew, who used to work on the till at Boots. “I’ve got my life back.”

Mr Cooksey, whose efforts earned him the title of Thrive and RNIB’s Inspirational Blind Gardener of the Year in 2006, said: “They are a happy bunch. It is really worthwhile for them. They get to a certain age in life, and then this thing happens to them, and they think life is over. But it isn’t – there is something they can do. That’s why they keep coming back.”

In a world without vision, the smells of the garden become more important than ever, whether it is Mrs Bartholomew’s sweet peas or the unmistakable aroma of a freshly dug carrot.

Some tasks are beyond the group – distinguishing small weeds from seedlings, for instance, and hand tools are easily mislaid.

“I put a hand trowel down and could not find it,” Mr Cooksey said. “So I went to town and bought another one. I came back, and the first thing I trod on was the flaming trowel I’d lost.”

To help them a small team of volunteers does the tricky jobs, such as digging, and children from the local primary school, Broom Valley Community School, are willing helpers.

Lesley Blakesley, a teaching assistant, said: “It was Dennis’s idea. He would be our knowledge and the children would be his eyes.”

The group’s vegetables have also proved to be a competitive success. Mr Cooksey has been entering them in the Rotherham allotment show, coming fourth in the first year, third the next and this year second. Next year, who knows?

Thrive is a small charity based in Reading with another series of projects in Battersea Park, London. To reach people across Britain, it relies on gardening groups such as Mr Cooksey’s to spread the word.

It has just produced a 40-page guide, drawing on the experience of gardeners and professionals who have successfully set up their own club. It has advice and information, tips from visually impaired gardeners, programme ideas and contact details and is available in large print, audio CD and Braille.