• Treated rough sawn timber 50mm by 25mm (2'' by 1'') in the following lengths: 4 times 500mm (or 19.7''), 2 times 650mm (or 25.6''), 1 times 800mm (or 31.5'')
  • Treated rough sawn timber 50mm by 50mm (2'' by 2'') in the following lengths: 2 times 800mm (or 31.5''), 2 times 500mm (or 19.7''
  • Up to half a mere of off cuts of treated rough sawn timber 50mm by 25mm (to reinforce corners as in photo)
  • Small hammer-driven galvanized staples, ideally less than 10mm or 0.5'' wide
  • Hot glue gun
  • Clear polythene sheet (UV stabilised is best) that the following lengths can be cut out of: 2 times 550mm wide by 650mm long (or 21.7'' by 25.6''), 1 times 850mm wide times 1700mm long (or 33.5'' by 67'')
  • Galvanized nails about 75mm (3'') long
  • Galvanized nails about 50mm (2'')long

How to build your mini greenhouse

Step one:

Build the bottom frame using the 4 lengths of 50 by 50mm timber, refer to diagram:

Step two:

Brace the corners as shown in the above diagram. Use off cuts of the 50mm by 25mm timber. Use the smaller nails to attach to the frame. Cut the ends at a 45 degree angle so they don''t stick out over the edge of your frame.

Step three:

Attach the 500mm lengths of 50mm by 25mm timber as shown in the following diagram:

Step four:

Lay the two 600mm lengths of 50mm by 25mm timber parallel to each other on the ground. Use the smaller nails to attach the 800mm length to the 600mm lengths so they form the roof frame shown in the diagram below. Then attach the frame onto the main project as shown:

Step four:

Attach the polythene, refer to the following picture as a guide:

Use the large piece to go right round the two largest sides and the roof in one go. The measurements given at the start of this plan should give you enough for some overhang to attach to the underside of the base and around the edges of the frame. Use hot glue to attach to the timber and then use the staples at regular intervals for extra strength.

Use the two smaller sheets of polythene on each end, overlapping the frame and the first sheet.

Using your mini greenhouse

Your greenhouse doesn''t have a floor as such. It works best if you lay your seedlings out on a hard surface (such as a concrete path) and then simply sit it over the top.

As the weather gets warmer, you can increase ventilation by propping up one end of the greenhouse with a small brick or piece of timber. This will keep the greenhouse well ventilated and help get your seedlings used to the climate before you plant them out in the garden.

I find I am able to give my warm-weather plants a 1-2 months head start in early spring with this greenhouse. It will protect your seedlings from those late frosts and save you taking up every sunny windowsill in the house with seedlings.