The RHS's top award is no bed of roses, but if you're ambitious, it's the best.

He is also the perfect pin-up for an industry that is increasingly being filled by middle-aged women taking on a second career and looking to escape the frantic rat run of office and urban life for the more tranquil rhythm of the seasons.

If meeting, or becoming, the next Monty Don is your idle daytime fancy, the place to go is the Royal Horticultural Society (RHS). With the changes the RHS is making to its Master of Horticulture (MHort) Award, the industry's top qualification has never been better suited to this new generation of green workers.

The Master of Horticulture, the equivalent of a degree, is Britain's top award for the green-fingered, dating back to 1913. This year it is undergoing its biggest overhaul in 20 years. The course, which until now required three years of home study, with only minimal supervision from a tutor for the dissertation, is being modularised, so that students can take it over a longer period or just focus on the specialisation they need, with each module becoming a stand-alone qualification. There will be tutorial supervision across the board, and a crash course for beginners in essay writing and research.

"The MHort is designed for people who want to do a degree in horticulture, but don't want to run up a debt," says Peter Rezin, principal examinations officer at the RHS. But despite its reputation and convenience, numbers on the course have been down in the last few years, with only one student on the course at the moment. That looks as though it is about to change.

"It's not easy to study some of the topics as a home study course," admits Rezin. "By modularising the course, the candidate can now select which ones he wishes to take. It's more specific to candidates' needs. It's far more flexible." Already, 45 people have applied for the new, modular MHort.

Candidates can pick and choose from six modules. These cover research, amenity horticulture (which is gardening for public spaces such as parks), production horticulture (gardening with a view to selling your produce), food production, business management and world horticulture. "There's more or less everything available," says Rezin. "From landscape gardening, through arboriculture and food production, to cut flowers." But whatever you do, make sure you wear your gardening gloves. "Horticulture is about practical plantsmanship," says Rezin. "At the RHS you have to get your hands dirty."

Which is exactly what Tony Davies, 46, enjoys about it. Davies is now the only student left on the old MHort. Although he was always a keen gardener, he admits to stumbling into horticulture as a career. After a stint in the South African army, Davies came back to the UK. "I didn't know what I wanted to do," he says. "Then me and a friend did my father's garden up. We did a pretty good job, and so he paid for us both to go to horticulture school." Davies has worked in commercial horticulture ever since, and is now deputy section manager for horticulture at Sparsholt College in Hampshire. But a lifetime's experience does not mean Davies has seen it all before. "You get a reality check when someone trips you up on things you think you know well," he says. "It focuses your horticultural expertise." It has also been very hard going, even for Davies, an examiner with the RHS. "I'm used to directing people to study, so it hasn't been too hard for me," he says. "But these changes will take the pressure off. At the moment I've got a dissertation due in, 600 exam scripts coming next week, and I'm holding down a full-time job. That's quite a lot to do." It has been well worth the effort, though, he says: "It's an excellent qualification, a recognition of attainment in the horticultural industry. A lot of the key posts at the college are filled by MHort holders."

A Master of Horticulture is not only the must-have qualification for academics but across the board, in the public and private sectors, and even abroad. German gardener and MHort holder Markus Radscheit always knew he wanted to go into horticulture. "It was never really a question," he says. "When I was young I had my own vegetable plot, with a barrel of rainwater, a conservatory and a crate of beer. As a kid it was a good place to go." Radscheit, 35, has expanded his responsibilities a bit since then and is now garden superintendent for the whole of Bonn's Botanical Gardens, responsible for the upkeep of 13,000 varieties of plants, more than four times the number that occur naturally in the UK, and 48 and a half staff (one is part-time).

Radscheit studied for his MHort while doing a diploma at Kew Gardens in London, and well remembers the slog of self-discipline. "While Kew wasn't easy, you always had someone to ask who would help you," he says. "For the MHort I was on my own - that was the challenge. It was extremely tough." He welcomes the changes. "It's good," he says. "Any changes that bring in a tutor will not only make it easier for people but will make the learning process more efficient. With a tutor there you'll learn more."

But in spite of the difficulty of doing the course untutored, he would certainly recommend it. "It was extremely useful," he says. Not only did it allow him to learn more about amenity horticulture - display gardens and botanical gardens - but the part of the course that focused on setting up a nursery, managing the accounts and marketing it has helped him to set up his own business on the side, Hortitours, organising summer horticultural tours to the UK.

The RHS did not just give Radscheit an education and set him up for a career, it also found him a wife: he met Junko, who now works for Botanic Gardens Conservation International, while working in the gardens at Wisley Park before moving to Kew. "I was a slave labourer there for a year - I think they call it a trainee," he says. "She was working there too."

You never know who you might meet at the RHS - perhaps even the next Monty Don. Behave yourselves, ladies, please.