High Desert Tufa Bed

Submitted by Weiser on

Hi Guys and Gals
For the past Year and a half I have been collecting supplies to build a modest tufa bed. Well this last week I finely got it completed. Thought I'd share a few shots of my acquisition.
It measures 11' wide across the front by 8' deep (front to back) the tallest point is 2' high. It's shape forms, roughly a half circle. The tufa used comes from ancient weathered hot spring formations. Many of the pieces are incrusted with colonies of lichens and desert mosses. I used decomposed granite for the fill heavily laced with 1/2 inch pumice, 3/4> altered andesite chips and small amounts of hummus and volcanic clay.
Since I live in a very dry climate I installed irrigation. I run two 1/2 inch feed lines under the mound, front to back, each with a ball valve so I can control the amount and type of irrigation I feel is required. One of these lines feeds 1/4 inch soaker tubing buried 6 to eight-8 inches deep throughout the mound. The other line feeds a pop up mini-sprinkler and can support drip fittings if required. Since water is a finite resource, that I pay dearly for, I excavated a shallow sloping swale under the bed. It is covered in a waterproof membrane, a layer of 1/2inch pumice and weed fabric (to prevent infiltration of silt). The swale drains behind the front center boulders into a small bog at the base of the front.

Front

Back

Left side

Right side

Comments

Submitted by Lori S. on Thu, 03/29/2012 - 22:33

:o  Looks great, John!  Interesting to hear about your water conservation measures.  Can't wait to see it planted up!

Submitted by Hoy on Fri, 03/30/2012 - 02:09

I like that one, John! Although it is very funny to build it I think the funniest part will be filling in plants :)

Submitted by Weiser on Fri, 03/30/2012 - 08:27

Thank you Lori
I know you put in a much more extensive bed in the last couple of years. I just hope mine looks half as nice planted.
This is my feeble attempt to emulate a natural thermal out cropping. I felt the best I could achieve was a half round, domed mound with random circular and semicircular terracing, stepping down along the sloping grades.

Hoy
I agree now the fun begins!! ;)

Submitted by Tim Ingram on Fri, 03/30/2012 - 10:45

I'm deeply envious! The great Northumberland alpine gardener Alan Furness made a circular tufa bed a little like this that I saw after the 2001 AGS Conference in Edinburgh, and I dearly wished I could have packed it away in my van! A tufa bed is getting higher and higher on the agenda. Will be great to compare the results that you and Lori have in such different climates.

Submitted by RickR on Fri, 03/30/2012 - 20:29

Really cool choice of rocks.
  I am wondering about the alkaline water running into the bog.  We have in Minnesota an ecosystem called a calcareous fen.  They tend to have a good portion of very unique flora.

Submitted by Weiser on Fri, 03/30/2012 - 22:55

I will have to test the water. The decomposed granite and altered andisite fill are slightly acidic, the tufa alkali, the pumice neutral.  The mix for the bog is fifty percent sphagnum potting soil and fifty percent decomposed granite.

I don't know what the ph will be. :-\

Submitted by DesertZone on Sat, 03/31/2012 - 21:30

This will be a great deal of fun as the progress grows. :)