Jennifer Schultz Nelson
Extension Educator, Horticulture
If you garden to any extent, sooner or later you will encounter a hypertufa planter. If you are unfamiliar with hypertufa, it is a lightweight stone-like material made from Portland cement, peat moss and either sand, perlite or vermiculite. Planters and decorative items made from hypertufa resemble carved rock. While lighter than carved rock and certainly less expensive than carved rock, hypertufa planters tend to cost a lot more than a comparable ceramic or clay planter.
Most people will have the same reaction I did when I first saw a hypertufa planter for sale: total sticker shock. Of course, I then thought to myself, "I bet I could make one myself and it wouldn't cost so much." Thankfully I work with Master Gardeners who also had the same thought about hypertufa and were willing to join me in experimenting with our own hypertufa creations.
Hypertufa is actually a synthetic version of a real type of rock called tufa, a naturally porous sedimentary rock. Tufa was popular in Europe in the 1800's for use as sinks and troughs for animals. Gardeners later discovered these troughs and sinks made great planters. Tufa rock became harder to find and more expensive, so gardeners developed hypertufa as a way to simulate the natural tufa rock.
A simple internet search reveals hundreds of recipes for hypertufa, and just as many methods to create the perfect planter. This number is not really surprising—it's a lot like asking multiple people how to make chili. Most likely each person's recipe is slightly different than the other, and the way they prepare it varies as well.
It may seem like an overwhelming task to choose the "best" recipe. Choose your hypertufa recipe just like you would choose a chili recipe—choose a recipe with ingredients you can readily obtain and a method you are comfortable with.
All hypertufa recipes will include a cement component and an aggregate component plus water. By definition, concrete is composed of cement, aggregate (hard material) and water. So hypertufa is essentially a specialized concrete mix.
A rule of thumb when trying a new hypertufa recipe is to buy the specific ingredients called for. If the recipe calls for Portland cement, do not substitute concrete mix. Portland cement is an ingredient in concrete mix, but they are not interchangeable in most hypertufa recipes.
Some recipes call for concrete reinforcement fibers. These small synthetic fibers help to hold the hypertufa mix components together in the finished planter. These are typically sold in one pound bags at large masonry or concrete mix companies.
The aggregate materials used in hypertufa—peat moss, and either sand, vermiculite or perlite are more economical if purchased in larger quantities, such as the what a greenhouse might use. It's certainly possible to use the smaller bags sold typically alongside houseplants, but expect to pay more in the long run.
Our group selected two recipes to try: one using cement, peat moss, and perlite, and one using cement, peat moss, and vermiculite. We found that each person preferred one recipe or the other, and it took some practice to mix the ingredients to the right consistency. It's important to wear dust masks, goggles and gloves when mixing hypertufa. Any fine dust from the components should not be inhaled, and the cement is caustic and will burn your skin. The mixing is best done outside if at all possible.
Use your imagination to choose hypertufa molds. Pretty much any container has potential for use as a mold. Consider both the inside and outside as surfaces to build your hypertufa creation on. We found that flexible containers worked best, as they were easy to remove once the hypertufa had cured. Meat trays, plastic bowls and serving trays created some of our best containers. Glass and plastic containers were the most difficult to remove. Actually, one is still stuck, more than two months after we made it!
Our conclusion was that while the materials to make a hypertufa container were relatively inexpensive, they took a lot of time to make, and created a lot of mess in the process. Certainly this is one reason they tend to be expensive in stores. They were definitely fun to make, and the results were beautiful! You can view our first experiments with hypertufa on our Facebook page. Just search for the "Macon County Master Gardener and Horticulture Program".
The Master Gardeners plan to have hypertufa containers available at this year's plant sale on May 1, 2010, and offer a hands-on workshop for the public to create their own hypertufa containers sometime this summer.