How to add drainage for garden bed?

[DIYH]

Hello 

I am building low retaining for garden beds. Approx 500mm high. Firstly, do I need drainage? I'm in Perth and pretty low rainfall majority of the year.

If so, can I just lay this Ag pipe in by itself or do I need to add gravel or similar and fabric? It says on the listing that it has a sock which prevents blocking. I have a gap in the brickwork for the pipe to be directed out of. Thanks! 

https://www.bunnings.com.au/brutus-65mm-x-20m-slotted-and-socked-agi-pipe_p0557568

Also, can it be cut for to size for each garden bed? 

[EricL]

Hello @DIYH 

I believe that it would be better to be prepared for that rare occasion where you suddenly have a large amount of rainfall and your garden bed overflows. Whereas if you had installed the gravel at the bottom, you would get very good waterflow in your garden. This would also prevent water from soaking the roots and causing your plant to get damaged. The socked agi-pipe can be cut to size and fitted into the available space.  

Let me call on our expeirnced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

[Dave-1]

Good morning @DIYH 

I can sort of picture your question, is there any chance of a few photos of the area? An overall step back one and any close ups of points you have particular questions about?

Drainage is always wiser, the cost of a 500mm retaining wall in money and time to build couldbe negated in a blink with any decent storm. For the small extra work you could help out with the lifespan of the wall. I prefer the socked 100mm agi pipe, mostly because there is less chance of it filling and connection to other pipes are less of an issue.

You will need gravel for the pipe to sit on and enough gravel to cover the pipe if youw ant it to do its best job, The gap you mention needs to be at the bottom of the long slow slope of the agi-pipe so water gravitates towards that point. It would also be wise to have somewhere for that water to go to after it exits the wall area.

Dave