Hello Clay ...

I have just started to experiment with this ... I was inspired to investigate this after James Curtis gave a presentation at Desert Green ... my first clay vessel was constructed with two pots and a measuring tube inserted at the top ... the flux rate of water out of the vessel seems like it would be very workable in providing water.

My initial rate was about ... 1 to 2 ounces of water per hour at a constant volume in the clay vessel. This is with two 4 inch pots.

Home Depot has small "self watering pots" that work on this principle .. they are glazed clay pots with an internal porous clay pot ... one fills the space between the two pots and the water moves into the root area.

I think there is a lot one can do with this concept and roof top or better yet balcony irrigation would be a great application.

My actual experience so far is very limited .. this spring I will run some more test.

Good Day ...

I have clients that don't water their containers, so this is very interesting to me. My question is- in a container, what happens when it does rain? Won't the soil get saturated and not drain?

I've been mulling on placing small plastic plant trays (the cheap clear plastic ones) down in the bottom of some of the larger containers- not enough to block all the drainage,but to hold some water.

Creatrix:
I see your idea but I would think you would be in risk of root rot if it happens to rain every other day or so for weeks on end during your rainy season..

Maybe put some volcanic rock in the tray too?

Claybones:
Check out this site about Ollas - an old Spanish method of slow watering plants where limited amounts of water are available. I ordered some of these and they are quite unique. As you said the clay pots must be unglazed so water can seep through and the top should be covered after the pot is buried so the water doesn't evaporate. Apparently this system is being used in desert areas quite effectively. http://www.swcp.com/~fellowship/ecm/ollas.html

I was thinking two or 4 4" diameter trays, maybe cut to 1" deep in a container 18"x 18" x 8-10" deep. I have also considered using disposable diapers- not lining the whole container, but allowing for drainage.

Still mulling the problem. I think using an outdoor potting mix with water retaining ingredients may also help.

I'm going to talk to them about getting some self-watering containers as well.

I'm also considering a cactus/sedum theme this year! We tried ornamental grass last year- but in black iron urns in full afternoon sun, even they croaked. At least they didn't look as dead as some of the other containers!