4ft Wide Wooden Greenhouses

About Our 4ft Wide Wooden Greenhouses

Every 4ft wide wooden greenhouse in this collection is a Swallow Lark, handcrafted in Yorkshire from ThermoWood redwood pine. ThermoWood is heat-treated at 212°C, which permanently changes the cell structure of the timber. The result is a frame that resists rot, warping, and moisture without chemical preservatives. Swallow backs this with a 12-year warranty.

The 4ft width fits comfortably in small gardens, against fences, and in spaces where a 6ft wide wooden greenhouse would feel cramped. All models include free professional installation, 3mm toughened safety glass, and an automatic roof vent. A mortice-locked door comes as standard. Choose natural stained finish or one of 9 painted colours to match your garden.

Which Size Swallow Lark Do You Need?

4ft Wide Wooden Greenhouse Comparison

* Matt's Pick — best balance of growing space and value in the 4ft range

Matt's Pick: Best 4ft Wide Wooden Greenhouse Best For: Small gardens where you want real growing space, not just a shelf Why I Recommend It: The 4x4 is tight once you're inside. The 4x6 gives you enough length for a staging bench at one end and growing space at the other. I always tell customers to go one size up from what they think they need. In the Lark range, the 4x6 hits the sweet spot. Price: £2,762 (installation included) View Product

Why Choose Wood Over Aluminium?

Timber greenhouses insulate 20–30% better than aluminium. Wood is a natural insulator, keeping heat in during winter and buffering temperature swings in spring and autumn. That means lower heating costs and less stress on plants during cold snaps. Our wooden vs aluminium greenhouse comparison covers running costs in detail.

ThermoWood also looks better in traditional gardens. The natural grain and warm tones blend with fencing, decking, and garden furniture. Swallow's painted finishes (Slate, Sage, Olive, and 6 more) let you match your greenhouse to your house or shed. Browse the full wooden greenhouse range if you need a wider model.

What's Included with Every Swallow Lark?

• Free professional installation — our team delivers and erects the greenhouse on your prepared base
• 3mm toughened safety glass — safer than horticultural glass and resists hail impact
• ThermoWood redwood pine frame — heat-treated at 212°C for rot and warp resistance
• 20mm PVC damp-proof barrier on the base to prevent ground moisture wicking up
• Stainless steel nails throughout — no rust staining on the timber
• Automatic roof vent — opens and closes with temperature changes
• Mortice-locked single door — 7ft 1” ridge height for comfortable headroom
• 12-year manufacturer warranty from Swallow GB

Frequently Asked Questions

• How much does a 4ft wide wooden greenhouse cost?

  4ft wide wooden greenhouses start from £2,575 for the Swallow Lark 4x4. The 4x6 costs £2,762, the 4x8 costs £2,958, and the 4x10 costs £3,154. Painted versions in 9 colours add £800–£1,000 per model. All prices include free professional installation and 3mm toughened glass.

• Is installation really free?

  Yes, every Swallow greenhouse includes free delivery and installation. Our team delivers the pre-cut frame to your address and erects it on your prepared base. Fitting a 4ft wide model takes 4–6 hours. You need a level, solid base ready before the delivery date. We check the base on arrival and advise if any adjustments are needed.

• What is ThermoWood and why does it matter?

  ThermoWood is timber heat-treated at 212°C to change its cell structure. The process removes moisture and sugars that attract fungi and insects. The result is a frame that resists rot, warping, and moisture damage without chemical preservatives. Swallow uses ThermoWood redwood pine, which is lighter than cedar but equally durable. It carries a 12-year warranty against structural failure.

• Do I need to treat or maintain a wooden greenhouse?

  ThermoWood greenhouses need minimal maintenance compared to untreated timber. Natural stained models benefit from a recoat of wood stain every 3–4 years. Painted models need a touch-up every 5–7 years. Neither requires the annual treatment that regular softwood frames demand. Clean the glass with warm soapy water twice a year — see our guide to cleaning greenhouse glass.

• What base do I need for a 4ft wooden greenhouse?

  You need a solid, level base of concrete or paving slabs. For a 4x4 or 4x6 model, 4–6 paving slabs on compacted hardcore will do the job. Larger 4x8 and 4x10 models benefit from a concrete pad. The base must be level within 5mm and extend 50mm beyond the frame on all sides. Do not use gravel alone — the frame weight causes settling.

• What can I grow in a 4ft wide greenhouse?

  Tomatoes, peppers, herbs, cucumbers, and overwintering plants all thrive. A 4x6 model fits 2 tomato grow bags plus a shelf of herbs. Wood insulates 20–30% better than aluminium, so spring seedlings get a warmer start and autumn crops last longer. The 7ft 1” ridge height gives comfortable headroom for tall tomato plants.

• How long does delivery take?

  Swallow Lark greenhouses are made to order with 8–12 week delivery. Each greenhouse is handcrafted in Yorkshire to your chosen size and colour. Swallow contacts you directly to arrange a fitting date. Painted models may take slightly longer due to the additional finishing process.