From the Internet researched by Herb Spady: 

The  Product

DRiWATER is a revolutionary new concept in living plant irrigation, patented by its inventor, F. Lee Avera (United States patent number 4,865,640. The outgrowth of a lifetime of research in food chemistry, DRiWATER is water bound in the form of a gel. When placed in contact with microbiological life forms found in soil, DRiWATER dissolves back into water at a controlled rate of flow. The product will continuously drip irrigate a plant or seedling over a period of time depending on the size of the application. In the quart size container, a seedling will be irrigated for three months or more without regard to the temperature or relative humidity.

DRiWATER is made of three non-toxic ingredients - pure water, food grade vegetable gum and alum. DRiWATER is absorbed by the soil, making it readily available to the plant's root ball. DRiWATER is safe around children and animals. DRiWATER is 98% water, by weight, and 2% vegetable gum and alum.

Patented in 1988, DRiWATER (a registered trademark) has been under a wide product testing program with governmental agencies, universities, and private sector end users. Extensive field tests have been conducted in arid desert conditions of the United Arab Emirates and many areas in the Western states with extremely difficult soils and weather conditions.

Guest speaker, Gordon Grenon of Island Garden Designs on Vancouver Island gave this recipe to the Mount Arrowsmith Rhododendron Society. Hypertufa is used to produce garden accessories such as used for trough containers.

3 parts dry peat moss
3 parts perlite
4 parts Portland cement
Hot water to mix to a consistency of cottage cheese.

BE SURE TO WEAR RUBBER GLOVES AND MASK WHILE MIXING.

Start small using a 3 gallon product mixed in a 5 gallon pail.  Mold with hands. Wrap the form in plastic applying a thick layer. Be sure the bottom is flat. Build the form upside down. Make a drain hole at the time or drill later. Dry at least two days. Remove the form. File and sand smooth. Shape and carve the container using a knife. Fiberglass or epoxy resin can be applied. Colored cement or paint may be used. To make mossy effect, brush buttermilk or sour mild on container then rub around moss in seed.

    As the refugees are driven out of Kosovo and make their way through the mountains and out of Serbia this spring, minuscule deposits of tufa are being formed by the melting snows high above.  The Alps of Greece, and this area, (the former Yugoslavia) are composed of limestone. The streams and run-off from high altitudes dissolve the limestone, and deposit it lower down in thin layers of porous rock called tufa.
    Here, some of the rarest jewels of the plant kingdom thrive in calcium-rich soil, enjoying a Mediterranean climate much like our own; wet, cool winters and dry, hot summers. Some of the most difficult alpine plants grow directly in the tufa, without soil, providing a challenge to gardeners in other parts of the world where soils are heavy, acid, or lime-free. Tufa provides moisture with perfect drainage.
    With plant explorers like Reginald Farrer bringing back alpine seed and glowing descriptions of these treasures from the Dolomites and other areas, gardeners wanted to grow them, but they could scarcely be kept alive in less suitable climates and deprived of the acute drainage and lime their root systems required.  The late Victorian era saw tufa being imported along with the precious alpines they coveted. Tufa was easy to transport; very hard and relatively light in weight when dry. Yet it was very easy to cut and shape when moistened again and pockets could be scooped out of it to plant the attractive little alpine plants in.
    In the 1920's, with natural tufa not easily obtained, keen gardeners developed a method of making a substitute out of various combinations of peatmoss, sand and pebbles, vermiculite and cement.  As stone water and feed troughs were discarded by farmers, it was discovered that these troughs were ideal for the hard to grow alpine plants. Eventually, the demand exceeded the supply for the troughs. In the 1930's, man-made tufa containers were inspired by English trough gardening.  This substitute for the naturally occurring tufa was called hypertufa and intended to replicate naturally occurring course textured porous tufa in the form of stone troughs-DMP

On one of my early trips up the Alaska Highway, I was prevented from travelling further over the dusty rutted road by an immense forest fire north of the Liard River crossing. With gas stops a hundred miles apart, one didn't consider backtracking to a coffee shop. I discovered the Liard Hot Springs.

Already familiar with stories of the Nahanni Valley and a legendary old prospector, Albert Faille, I whiled some hours away in the spruce and tamarack forest and open meadows. The bogs were traversed by a rickety makeshift route of logs and planks constructed by the army during the war. From the small deep hot spring, encircled by trees, I could hear the snorting of a moose, and beavers splashing in a nearby pond -a welcome respite from 900 miles of gravel road.

I let my mind wander to the Nahanni where the Liard River flows and thought of old Albert, perhaps in his 60's then, who entered this valley of breathtaking plateaus, lurid tales, headless skeletons, and unique geological features, alone, year after year, to search for gold. I pictured Virginia Falls, this continent's most spectacular undeveloped waterfall (twice as high as Niagara) tumbling down into one of the deepest river canyon systems in the world. Below the falls there are 8 km. of continuous rapids and standing waves. It flows through Deadmen Valley and to Rabbitkettle Hot Springs and the giant Tufa Mound. The Mound is formed by warm water radiating outward and creating, millimetre by millimetre, an intricately terraced dome of tufa more than 27 metres high.