People just know that gardens are therapeutic. But, until recently, good evidence for this was hard to find, says John Smith, team leader at Suntrap Gardens in Edinburgh.
"At one time, if you said `gardening's good for you', you couldn't prove it. Now there are research results. Loughborough University, for instance, has done a lot of work. It makes it easier to explain the benefits of what we're doing here with young people."
Suntrap was originally the home of philanthropist George Boyd Anderson, who bequeathed it to the nation for horticultural education - a bequest which West Lothian's Oatridge College now fulfils at the three acres of lawns, rock gardens, woods, beds and borders in the west of the city.
For two years, the garden has been hosting regular visits from a group of Skills for Work pupils from Dunbar Grammar. All 10 have just completed the course. But there's more to this than the usual story where youngsters for whom school doesn't suit get a chance to thrive in a hands-on environment. People are important as well as place.
Mr Smith takes a keen interest in working with learners who need extra help to fulfil their potential. "It's about looking at them as individuals and trying to match what they want to achieve. It's about not putting everybody into one box."
This interest led the Oatridge College lecturer to pursue a part-time diploma in social and therapeutic horticulture from Coventry University. He has won several awards, most recently from the Royal Caledonian Horticultural Society for "outstanding work in using horticulture to help young people with learning difficulties and vulnerable adults".
Vocational learning still suffers from an image problem in schools, he believes. "There's this feeling that if they don't know what to do with you, they stick you in gardening or something.
"Schools still have to get good academic results. That hasn't changed. But it doesn't work for some kids. Often, they grow more disillusioned because they're being set up to fail. The positive side is that it gives us the chance to help them turn things around. They love coming here and learning real skills they can use in their own lives."
Gardening, landscaping, laying slabs for paths - these are all interesting and rewarding activities in themselves. But they are also valuable preparations for later life. "They learn to take care of the environment, for instance. So we grow things organically. We have barrels to collect rainwater, which they use for watering the planters they set up themselves. They love all that."
Like all Skills for Work courses, rural skills comprises paper as well as practical activities - all of which normally take place in a local college or in a school with support from the college. Suntrap Garden has adopted a different model, says Mr Smith.
"The school delivers the employability skills, while we do the practical units - estate maintenance, crop production, landscaping. It works really well. We did talk about delivering all of it in school. But these kids are socially conscious. They would have been walking around in dungarees, getting stick from other pupils. That would have made it hard for them to enjoy the course."
Suntrap has also been working closely with young people at Glencryan School, Cumbernauld, where the needs are different but the approach is similarly learner-centred. "We have developed a plant-and-grow course for people with complex needs. It is rewarding - and fun - for them and us. It's not all about gardening. It's about people.
"I remember a lady in one of the groups who come here from day centres. She would never look at you but always down at the ground. Then she put a plastic spider in my hand one day, after about two years, and we both laughed. Since then, we have eye contact and she talks to me. The communication is there. That's what it's about. It does take time though."
It's a word that comes up often in conversation with John Smith. Like all good gardeners, he has a lengthy perspective and a feeling for the time it takes to get the best out of growing things - whether it is flowers and vegetables or young people with additional needs, emotional difficulties or undeveloped social skills.
It is time well spent, he firmly believes. "We grow things organically at Suntrap. If you stop using chemicals, after about five years you don't have a problem. So we have ponds with frogs which go for the slugs. We have hedgehog and bat houses. We create habitats that encourage natural predators. Eventually, the balance of nature takes over. If you work at it long enough, you don't have pests."
Besides courses for schools and day centres, Suntrap Garden, which is open to the public throughout the year, also provides a range of classes and workshops on gardening, garden design and horticultural skills.