Greenhouse plans

Before you start

Build your own greenhouse

Did you know that you can construct your own growing house for much less than the price of a kit set or commercial structure?

Our greenhouse plans use a timber frame and a clear polythene covering. This structure is not comparable to commercial glass houses or double insulated plastic structures, and thus is not suitable for year-round growing in very cold climates. But if you are a keen outdoor gardener who wants to extend your growing season, then this plan should more than meet your needs.

Before you decide whether to go ahead and build your own greenhouse, think about what it will be used for. If you want to give your seedlings a head start before planting them in the main garden, you will probably be best setting your greenhouse on a concrete base, and perhaps setting up shelving inside.

If you want to grow tender summer crops to completion inside the greenhouse, you may want to sit the structure straight on top of an existing garden bed. The heavy timber floor frame in our plan makes the greenhouse very versatile.


Standard framing timber is not recommended for this project because of the level of dampness the frame will have to stand up to. We recommend using timber treated to an outdoor grade.

Our plan assumes you use rough sawn timber (not dressed).

These are the key materials you will need to follow our plan:

  • 44m of 50mm by 50mm timber*
  • 1.6m of 75mm by 25mm timber
  • 4m or 50mm by 25mm timber
  • 7m of 100mm by 75mm timber for the base (2x2m and 2x1.5m lengths)
  • 15.5m2 of heavy-duty, clear, UV stabilised polythene**
  • Two large door hinges and a latch
  • 75mm jolt head nails
  • Staple gun with stainless steel staples
  • Hot glue gun or silicone sealant

*allows 5% extra for wastage/off cuts

**Actual coverage area (doesn't allow for wastage/off cuts)