It is amazing what can be done with 1,500 plastic bottles and a bit of wood. "Actually, a lot of wood," says Ian McNair, acting principal teacher of pastoral care at Shawlands Academy, Glasgow, "240 feet of it. That's what you need to build one of these greenhouses."
The rapidly-growing glass-free structure will become part of the school's new vegetable garden, which pupils are reclaiming from a patch of waste ground next to the school and across the road from the red sandstone flats on Moss Side Road.
There was a garden here once before, says headteacher Ann Grant. "It belonged to the janitor's old house, but when he moved out, no one looked after it for years. It was getting more of a mess all the time. So I had a chat with the local residents, and they were keen for us to do something with it."
The pupils who have done most - and already have the space looking like a real garden - are Mr McNair's Prince's Trust xl group and the bilingual support unit supervised by EAL (English as an additional language) teacher Karen Weatherstone.
"Excuse the dirt," she says, extending a soil-stained right hand. "Neither Iain nor I is a keen gardener. But we are picking it up fast, along with the kids."
Outdoor learning is a fabulous way to develop their language skills, she says. "We get newly-arrived kids from schools all over the city, whose English has been assessed as not up to the mainstream. Working here in our garden - and on forest schools, which we do every week - gives an authentic stimulus, a natural reason to chat to each other.
"It develops their vocabulary and language structures. Once they are talking about things that interest them, we build on that in class. We develop spelling strategies and punctuation and get them to write grammatically-correct sentences."
All around the garden, youngsters are digging and hoeing, tackling the weeds that spring up almost overnight at this time of year. Some look adept, but others have more enthusiasm than skill.
"Awareness of risk and handling tools is one of the first lessons they get with forest schools," says Mrs Weatherstone. "We keep an eye on them all the time, of course."
At this point, a soil-encrusted weed soars past, expertly tossed by a young boy confidently wielding a fork. Thabo Ndluvo, 15, came to Glasgow in January from Zimbabwe with no English at all. He says: "I'm going to plant vegetables here, maybe potatoes or beans. If you speak to me, I know what you are talking about now. I can read, too. But I don't know how to use a computer." He smiles and adds: "When I first saw someone use a computer I thought they were watching TV."
The real gardening expertise today comes from Abi Mordin, project manager with a local environmental charity, who is showing the youngsters how to section off raised beds, using long branches they cut this morning.
"Urban Roots does community gardening, conservation, biodiversity and climate change in schools across the south side," she says. "We spend six weeks on different topics: food, energy, transport, waste and consumption. We look at causes, effects and what you can do about it. We have been talking about how Shawlands can implement the Global Footprints project - a whole-school approach that gets many different departments involved."
This garden ties in holistically with all that, Ms Mordin says. They use kitchen waste to make compost and the youngsters get to cook and eat the vegetables in home economics.
Working outdoors is way better than being in a classroom, says Aimee Jack (S4). "I have been clearing rubbish, then raking the soil. There are carrots and potatoes there that somebody planted already, and we are going to plant more.
"We have been out to my old primary school to help them with their garden. It is fun. You have a laugh, but you are learning stuff, too."
While the bilingual and xl groups do most in the garden at the moment, other departments also plan to take advantage, says Mrs Weatherstone. "English will use it as a reading area and for talk activities. Geography have done weather recording. Technical are supporting us with all the materials."
Behind a wall, the eco-friendly greenhouse is beginning to take shape on the grass. "Let's get the bottles out, guys and I will show you what to do with them," says Mr McNair. "You cut the bottoms off first, then feed these long canes through them."
Gardening is just one aspect of xl classes, says Connor Hamack (S4), who is first to have a go. "You learn how to help each other, and how to work together. It is about teamwork."
At this point, a gust of wind catches the capacious polythene cover over the huge pile of two-litre bottles, which Connor's classmates are delving into. "Don't fling them all out, stupit!" Connor calls out. "They are going to fly away."
He turns back with a smile. "Aye, it is all about teamwork. And communication."
Plastic Bottle Greenhouse
http:www.reapscotland.org.uk wpcontent uploads201104Plastic_Bottle_Greenhouse_Instructions_2004.pdf
Prince's Trust xl clubs