Keyhole building ideas

I would like to build a keyhole here in TX (and if it goes well, probably build several more), but am having trouble finding bricks or rocks for free. Any ideas on how to build one out of wood? We have a lot of oak from our property, but I'm not sure how quickly it wil rot. With out high humidity, things rot VERY quickly, and as also cannot use wattle and daub (sp?) to build walls because it just dissolves. Any other ideas for how to build a deceely lasting keyhole? I have access to glass bottles, but am not sure how to secure them so they won't wash out other than using cement, which gets expensive when using that much.

About a month ago, I built a keyhole garden with wattle walls.  The day I finished, we had an exceptionally hot and dry spell.  So hot and dry, that the newspapers are complaining that it's the dryest summer since the 1940s (Not true, but it sells papers and helps people be more water conscious, so that's good).  I expect this garden to need repair in about 3 years, and last about 5 to 8 years.  That's also about how long I expect it to take for all the organic matter in the bed to break down, so it will be time to build a new one then anyway.  I wanted to make it from all compostable materials for an easy takedown.  

Also, check out the keyhole garden thread.  These are African style keyhole gardens with the compost in the middle.  There are lots of different construction methods.  Very interesting stuff.

I just dug a hugel mound down about three feet and loaded it with old firewood and etc.  I didn't put any soil amendments in it.   I used Logs as a perimeter.  The whole thing is covered with fennel and perennial seeds.  I planted annuals to see how they would do.  

Not sure if this is in the ball park.


Regards, Scott  

That's a good idea - that way I wouldn't have to build walls at all. Thanks! I already have a hugel mound in the back, "aging" that I'm really excited to plant later on!