After doing some research around sub-irrigation I think I've come up with a cheap method of creating a SIP pot (the 20L pails are expensive in Aus)
- 9.3L Bucket
- ~40cm length of 2" Corrugated Drain Pipe
- ~30cm length of 13mm rigid hose
The rigid hose will be trimmed and a short section used to provide the overfill drain (level with the top of the corrugated pipe, through the bucket wall), the remaining long section will be used to feed water into the drain pipe in the bottom.
The space in the centre of the corrugated pipe will be filled with gravel (slightly lower height than the drain pipe) and shade cloth layered over this.
A mix of 5-1-1 Pine bark - peat - perlite (with some fertilizer and lime depending on the plant) will fill the space above the shade cloth. The surface will probably be covered in straw mulch
Before I go plant 20-30 of these, I'd be keen to know;
Recommended amount of gravel? level with overfill pipe? half the height of the corrugated pipe (to allow more moisture wicking)?
I'm also planning on using builder's plastic sheeting in the bottom of regular pots to block the drain holes, any recommendation as to whether just to line to above the water level, or the entire pot?