Sub-irrigation planter bucket setup

Question

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?

Answer 1

Never heard of this before other than this is one of nature's way of watering plants. I'm a little concerned about the water being able to get out of the pot. Does the water just sit at the bottom until taken up by the plant? I don't like the idea of sitting water but I am still open.

There is one thing I do understand and that is perched water-tables. It is contraindicated to put gravel in the bottom of a pot (the thought being to increase drainage through the bottom and to save money on soil and to make a pot heavier so that it isn't blown over by wind) because the difference in pore spaces is so great that the soil pore spaces have to be saturated with water before the water can move into the larger pore spaces of the gravel. Less air for the plant and diseases can proliferate while the soil is so wet. I realize we are going the other way, from down to up.

In the landscape I can see this subirrigation working well. I'm a little concerned about enclosed pots like this. I think you should try growing plants in this pot first before you invest in 20 or 30. This is very interesting! I hope this works well...