Pots with a Personal Touch: Hypertufa

Years ago at a flower show, a group of rustic garden containers caught my eye. They were made from a stonelike material known as hypertufa, which mimics a type of rock.

As a crafts editor for Martha Stewart Living and a ceramicist, I was intrigued to learn that the planters were composed of just three accessible, inexpensive substances: perlite, Portland cement, and peat moss.

When I realized pots so impressive could be shaped using basic molds, they became even more appealing. It's not often that a process as rudimentary as making mud pies yields such a sophisticated result.

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Hypertufa was developed in the 1930s to replicate the stone troughs that were popular among English gardeners in the late 19th and early 20th centuries. The lightweight stand-ins were not only easier to come by, but also easier to transport. Thanks to their porous nature, the pots were ideal for plants needing good drainage. Hypertufa containers are still practical in the garden and simple to create.

To make a pot, you'll need to fashion a mold from a pair of vessels -- the mixture is poured between them. I experimented with various objects, such as milk cartons and metal bowls, and also constructed wooden molds. Because the medium captures subtle textures, baskets and leaves can be rendered in "stone," while clean-lined molds offer a sleek, modern look.

After making many containers and a couple of tabletops, I found the process quite rewarding. It is not an exact science, which is part of the fun: Every pot has the potential to surprise.

Basic Hypertufa How-To

1. Choose mold: Make a mold from two nested vessels, so you can pour the mixture in the space between them. Both should have sides that are straight or taper out; the gap between them should be at least 3/4 inch for smaller vessels and 1 1/2 inches for larger ones.

2. Mix materials: Wearing gloves and a dust mask, mix equal parts white Portland cement (gray can be substituted for nontinted vessels), perlite, and peat moss in a large bin; stir in masonry stain if desired. Add water gradually to reach the desired consistency.

3. Fill mold: Coat vessels with mold-release spray. Pour mixture into the outer mold to a 1-inch depth for smaller vessels or a 2-inch depth for larger ones. Set interior mold inside, centering it (you can fill it with sand to steady it). Continue adding mixture between vessels. Tap exterior with a rubber mallet to minimize bubbles. Cover with plastic; let set.

4. Finish hypertufa: After removing mold, drill holes into the bottom of pot using a masonry bit, for drainage; smooth the top edge of pot with a planer file. Wrap it with plastic, and let cure for several weeks.

Flat-Weave Basket Hypertufa

Flat-weave baskets gave these large containers their checkered finish. A spray of New Zealand flax underplanted with oxalis provides a touch of drama.

DIRECTIONS

Mix 8 quarts peat moss, 8 quarts perlite, and 8 quarts portland cement. Add water until mixture has the consistency of cottage cheese. Makes 1 basket (12 by 13 inches).

SET TIME AND RELEASE

Let set for 36 hours, then gently remove interior container. After another 12 hours, cut away basket.

Wicker Basket Hypertufa

Cast in wicker baskets, these pots feature a ribbed pattern that contrasts with the delicate violas inside.

DIRECTIONS

Wrap exterior of basket with duct tape to help prevent leaks. Mix 8 quarts peat moss, 8 quarts perlite, and 8 quarts portland cement. Add water until mixture has the consistency of cottage cheese. Makes 3 to 4 baskets (3 1/2 by 14 inches).

SET TIME AND RELEASE

Let set for 36 hours, then gently remove interior container. After another 12 hours, cut away basket.

Milk-Carton Hypertufas

Milk cartons used as molds create cube-shaped hypertufa vessels, each sized for a single succulent. The tint variations are achieved by mixing in masonry stains.

DIRECTIONS

Mix 3 quarts peat moss, 3 quarts perlite, and 3 quarts portland cement. Mix in 13 1/2 tablespoons masonry stain (1 1/2 tablespoons per quart). Add water until mixture has the consistency of cottage cheese. Makes 3 to 4 small boxes (4-inch cubes or 4 by 4 by 5 inches).

SET TIME AND RELEASE

Let set for 24 hours, then gently remove interior container. After another 24 hours, tear away carton.

Bowl Hypertufas

These rounded pots owe their smooth, elegant forms to a kitchen workhorse: the metal mixing bowl, in two sizes. Masonry stain added to the basic hypertufa formula imparts a cool blue hue. Mixed groupings of dwarf plants -- confiers, ground covers, and hostas -- fill the hemispheres.

DIRECTIONS

For a 6-by-11-inch bowl, mix 2 quarts peat moss, 2 quarts perlite, and 2 quarts portland cement; for a 7-by-14-inch one, use 3 quarts of each. Mix in masonry stain (1 1/2 tablespoons per quart). Add water until mixture has the consistency of cottage cheese.

SET TIME AND RELEASE

Let set for 36 hours, then gently remove interior container. After another 3 days, turn bowl over, and tap bottom with a rubber mallet to remove hypertufa.

Get the How-To for the Faux Bois Hypertufa

Get the How-To for the Leaf Tabletop Hypertufa

Sources

Peat moss (#809383) and perlite (#809352), by Miracle-Gro, from Home Depot. Gray Portland cement and carpet tape (#50-605), by Roberts, from Home Depot. White Portland cement, available at masonry supply stores. Universal Smooth-on Mold Release (#66MR1), from the Compleat Sculptor, sculpt.com. Nasum basket (flat-weave), from Ikea. Mason stains, from eceramicsupply.com. Wicker baskets, from B&J Florist Supply, 212-564-6086. Texture mat, in wood-grain pattern (PA 01-4), from chineseclayart.com. 1/4-inch Plexiglas, by Stanley, from Home Depot. Surform Plane Type, regular cut blade (#185515), by Stanley, from Home Depot.