Monday, September 26, 2011

A Word on Hypertufa by Judy Huckaby

When a hypertufa class was offered through the Jefferson County Master Gardener program, I immediately signed up to become an instructor.   I learned that tufa is compressed volcanic ash that has been mined for centuries in order to be carved into watering troughs and sinks.  Gardeners began to covet these containers for their rugged looks and soon the troughs became expensive and rare.
Somebody somewhere down the line had a flash of brilliance and came up with a recipe to make garden containers that look and are waterproof like tufa, but are lighter in weight.  Called hypertufa, the prefix “hyper”  can mean excess, exaggeration or above and beyond.  Regardless of the meaning, hypertufa containers are usually planted with “alpine gardens” because they leech alkalinity and these plants can take it.

Duane Davidson’s lovely circular red colored pot.

 That’s not to say that all that can be planted are hens and chicks and things like that.  One of my fellow hypertufanists planted blooming oregano in hers.  And I’ve seen some beautifully planted with other things.

Not satisfied with the standard recipe, I realized that hypertufa  is a concrete mixture.  Concrete is cement mixed with aggregates.  To make traditional hypertufa, the aggregates are perlite and peat moss.  Mix 1 part cement to 1-1/2 parts each of perlite and peat moss, toss with a bit of water and cram into a mold.  Keep covered and moist, wait a curing time of 4 weeks or so, and viola a hypertufa container is born.

The traditional look is gray and so gray cement is used.  I learned about white cement,  a more refined cement product which costs twice as much.  Aggregate can be lots of different stuff:  sand, coffee grounds I am told, vermiculite, aquarium pebbles, the list goes on.  The only thing constant is the ratio of 1 part cement to 3 parts aggregate.    For my latest container, I used white cement, vermiculite, and a finely ground perlite to create a mixture that could be carved a day after it was molded. The texture is a bit different, and it is rather heavy, but to me it still looks like a weathered pot that possibly came from stone (who knows, maybe even tufa).

Vermiculite Pot
 The Jefferson County Master Gardeners have taught a very successful workshop on hypertufa.  Participants created a pot about 8 inches wide and long and 12 inches high using cardboard boxes as molds.  In the garden, these containers will provide a little nook where alpine plants can be featured.
The workshop was so successful, that the Master Gardener instructors are debating whether to offer another workshop before Christmas.  Fall is an excellent time to create hypertufa as the pots cure better in cool temps.  Should the workshop come to pass, it would be offered in time to make a container or two for Christmas gifts.  A gift of a handmade hypertufa to a gardener would go a long way in providing holiday cheer.

Needless to say, learning how to make hypertufa has set me on fire for more experimentation.  Rex Murfitt’s garden in Victoria, British Columbia offers me lots of inspiration. (The picture is from Creating and Planting Garden Troughs by Joyce Fingerut and Rex Murfitt, a good read if you want to know everything about making and planting a hypertufa pot).