On our plot there is planning permission for a large greenhouse, (33 by 9metres). But how would we afford to build it was the question. I had reused second hand double glazing units in various DIY projects, so I wondered if they would work for a greenhouse and if I could get enough. While talking with a friend who is hot on recycling, he said he had seen a lot of good units in skip of a doubling glazing company near his home. He got talking to the manager of the company about this. The manager explained that there is about 10% waste in the double glazing industry. Sometimes they get the measurements wrong, sometimes there is a little scratch, sometimes it is just a slight wipe mark left on the inside of the unit, but they all end up in smashed in a skip on their way to the landfill site. My friend told them what we wanted to do and asked if we could have the rejects for our project. The conversion revolved around doubts about building a greenhouse with them but the manager didn't like all the waste. Once he realised that we hadn't the money to be in the market for their services, and that it would save them money to give the rejects to us rather than send them to the landfill, he agreed to give them to us. Bless his heart. So over the next two years we collected units for our grand project. A big thank-you to Ron and the manager.

Ella and I had been seeing a beautiful glass building in our dreams since 1993. A place where all those lemons, oranges, grapes, bananas, passion fruits, mangoes, (the list goes on) could be grown and save all those polluting air miles that fill our grocery bags. At the same time we saw a building to inspire, reflect and meditate with the flow of life – a place to grow plants and people, sheltered and warm in this country without pouring masses of heat into the

first on a much grander scale – but this one was to arise from waste.So in June 2001 I started building it. We knew we wanted two sections to it, one of which could be heated in the winter to protect the tender plants and provide early propagation for our seeds. Also the warm room could then be used for teaching and working in the warm even in the depth of winter. We also wanted

something of a round or octagonal feeling too it. So we settled on the plans below ( 12m x 7m at the widest point) which give the octagonal section the advantage of south-west and south-east faces even though the room is at the north end on the building. We also decided on a timber frame construction using logs (from some local conservation clearing work) to construct the window support walls and the north end wall, since they have such good insulating properties. The foundation plinths were made from the waste quality chippings from a local small scale quarry with sand and a small amount of cement added. And then blocks and a damp course to protect the wood.

Then came the puzzle, which thankfully I had already figured out. You see the glazing units were all different sizes, how could I get the right fitting units from about 300 to choose from. Without proper planning each new window would require

endless toing and froing and holding windows up to the space to find a fit. Plus the end result would probably not be the most efficient use of what we had available. So we measured and numbered every unit then I got out the CAD programme in my computer and drew each window unit to scale and did a jigsaw on screen. I allowed myself leeway through the use of various thicknesses of timber in the frame making. For example 2x2 inch when the gap was small and 4x2inch when it was wide or even bridging two 2x2 inch uprights with some 4,5 or 6x1 inch planking. The result is a pleasing mixture of irregularity framed by the regular pattern made by the support structure.

I made the frames by routing a groove in the timber (a router is a machine designed to make grooves) and then setting the glass in with glazing sealant.

We had eight large recycled skylights to put in the roof. These have proved a very effective means of temperature control. On hot days the heat easily rises up through them and on still days it even creates a light breeze in there so the space never gets overheated. The roof was our biggest challenge. It needed to be transparent and waterproof, yet in the octagon, heat retentive. Also the roof pitch is shallow to keep it in the height of the planning permission and thus more difficult to leak proof with a slower runoff. So we went for a compromise, using high quality corrugated plastic as the outside skin and a double glazing jigsaw for extra insulation in the octagon. The skylights posed a problem since they were designed for a steep pitch roof and thus collected water at the bottom of the frames. To deflect the water I sealed in position strips of glass that covered where the water would sit. Also the storm seal design did not work at that angle. So I covered the frames with strips of tractor tyre inner tube so the water could not get in the first place.

The floor of the front part and the bed edges throughout were made from blue lias stone from our small local quarry. The stone serves as a storage heater keeping it warm at night through spring, summer and autumn. There is a wood floor in the octagon since there was too much of a slope to use stone.

I built a long potting bench in the front section which brought on this years seedlings very well. The beds all are direct into the earth and the banana passion fruit, tomatoes and peppers amongst others are all growing well. We also have lemons and oranges in fruit and a dwarf banana which will be planted in one of the beds in due course – yum the dream has come true.

The richness of the environment is enjoyed by all who come here. Being amongst Mediterranean and tropical plants in the warm is deeply soothing to we apes who somehow remember the environment of our ancestors.

This all cost less than £4,000, and it took a year and a half of my spare time to build. But out of waste a delightful place to work and grow in has been born.

On a national scale a huge amount of double glazing is being wasted. There is an opportunity here for some resourceful green builders to strike up some deals with the manufacturers and construct low cost hot green houses for the permaculturally and organically minded growers who do not have the many thousands of pounds spare to construct places with perfectly matching windows. And some of us prefer that they don't anyway!