Norhage Tre 300 10x20 Wooden Greenhouse

The Norhage Tre 300 10x20 wooden greenhouse gives you eighteen square metres under a Swedish pine Gothic arch. Six metres of length is enough to grow in succession. One bed crops while the next is still coming on.

The arch is structural, not decorative. Solid plywood ribs carry a 280 kg/m² snow load and stand up to 25 m/s winds. Swedish pine makes up the base frame, the connecting beams, the front section and the door.

Twin-wall polycarbonate does two useful things at once. It insulates, because air sits trapped between the skins. It also diffuses, spreading light down the length rather than throwing hard shadows across the beds.

Six millimetre twin-wall is standard, with 10mm and 16mm available. The thicker sheets hold more heat overnight. That matters once a greenhouse is long enough to lose warmth through its ends.

Wood is not inert. It swells and shrinks a little through the year and the odd fixing needs nipping up. Aluminium avoids that, at the cost of how it looks in the garden.

Please note the glazing arrives uncut, at standard sheet sizes. A finished frame never lands exactly on its nominal dimensions. Full sheets are supplied so nothing ends up short, and you trim them as you go.