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What You Need to DIY a Hypertufa Trough

by Timber Press on August 2, 2018

in Craft, Design, Gardening

In this trough-building method we’ll tackle creating a trough by forming it inside a mold. This is a viable, popular way to create beautiful planting vessels, and Lori Chips author of Hypertufa Containers has the expert advice you need.

Hypertufa Mix Recipe
(buckets referenced are 5-gallon)

  • 1 1/2 buckets of coarse perlite
  • 3/4 bucket of sieved peat moss
  • 1 full bucket portland cement, type I/II light
  • 1 good-sized handful of fiber mesh

In very broad terms, depending on mold size, depth, wall thickness, and other variables, this amount of mixture will make roughly four small to medium-size troughs. For two smaller or one large trough, halve the recipe.

1. Place the ingredients in the wheelbarrow. Follow the order listed, because perlite has a tendency to float up and both the cement and peat tend to travel down.

2. Scatter the fiber mesh across the top. Separate it somewhat as you scatter.

3. Mix the dry ingredients thoroughly. Make sure there are no pockets of perlite or peat anywhere.

4. Add water slowly. Add the water in stages and mix between additions, until the mixture reaches the consistency of rather thick oatmeal. If the mix is too dry, the chemical process that bonds the mixture will be impeded. I have seen my fair share of failed troughs that were too crumbly even after curing because there was too little water mixed in to start off the chemical process. If the mix is too wet, wait 15 or 20 minutes. The consistency may correct itself as the dry peat absorbs water. Or, you can add dry ingredients proportionately.

Follow these steps and hopefully the Goddess of Hypertufa Consistency will bless you with perfect mixes. Just remember, She never blesses you 100 percent of the time.

Forming the Trough
There is something intrinsically satisfying and primeval about sinking your hands into this medium and creating a vessel. Tribes have been working like this for centuries to make everything from sacred cups to plates in which they smashed corn. Trough making is your chance to join the tribe. The hypertufa is mixed; you are ready to go.

1. Wet down the inside of your mold completely. It is handy to keep a watering wand ready to use, as well as at least one small watering can.

2. Line the mold with the thin mil plastic drop cloth. The thin mil adheres best to the wet mold. Try to minimize folds and creases by intentionally pleating and making flat tucks in the sheet. This way it is easier to avoid folds occurring unpredictably and hurting the integrity of the piece. By the way, kitchen plastic wrap is never wide enough, sticks to itself, and is a pain to work with. Go with drop cloth.

3. Make certain there are a few inches of overhang on all sides, then cut to fit.

4. Pat the hypertufa inside the mold. A handful at a time, begin to form the bottom of the trough by patting the hypertufa in place. This is called the patty-cake method. The exact techniques of the patty-cake method and the consistency of the mix is open slightly to preference, but you don’t want a pourable mixture or the mold would need an insert to retain the walls. When you patty-cake the piece together, the medium must have more body and be able to stand up on its own.

Within reason, the thickness of the walls is a matter of choice. Make them thinner than three-quarters of an inch and the piece may be too fragile. Make them thicker than two inches (depending on the overall size of the mold) and the aesthetics may not be pleasing. I can tell you unequivocally that elegant is much better than a clunky porridge bowl that looks like it came from the Black Forest in the Middle Ages.

A terrific back saver is having those small empty containers (without holes) for scooping up mix and carrying it to your workspace. Anything waterproof and lightweight works. This offers the added benefit of allowing each artisan to customize the moisture in the mix. Just as the needs of each piece vary, so do the preferences of each trough maker.

5. Begin building up the sides of the trough. I like to work in courses, similar to building a stone or brick wall. Err on the side of a slightly dryer mix in the bottom course or two, as a wetter mix will travel downward. Take the time to press the mix into the corners to prevent gaps. This is a little like making a coil pot, a structure that potters know well. You are using each handful of material to make overlapping joins to form courses up the wall of your mold. You can use the sides of the mold to press against as long as you are also pressing the handfuls to form a bond with the preceding course. Gently and carefully firm each new handful onto the last so that no weak spots develop. Bring the walls up to the desired height. The deeper you make the trough, the more plant choices you will have.

6. Poke drainage holes. Once finished, use a screwdriver or your finger to poke an adequate number of drainage holes in the bottom, being careful not to weaken the structure with too many, or with holes too close together. Make one hole three-quarters of an inch to one and a half inches for a trough twelve inches square or less; add more holes for larger or longer troughs. Cover the trough and the mold well with plastic and allow it to set up for the night.

7. Finish up. At the end of the day, the mix must be used up or thrown away (which is painful, after all your careful work of mixing!). It will not hold until the next day, and could ruin whatever you try to hold it in (the wheelbarrow, for instance). Instead, use up leftover mix by making a tiny trough to hold succulents that don’t mind a shallow pot. All tools need to be cleaned, and the wheelbarrow must be washed out.

Once the trough have been unmolded, you’ll finish by texturizing, curing, burning off, and weathering the form to prepare it for planting.

Lori Chips is the alpine manager at Oliver Nurseries in Connecticut, pressing the boundaries in the art and science of trough making and planting. She writes for the North American Rock Garden Society, has judged at the Philadelphia Flower Show, and is the recipient of the Carleton R. Worth Award for horticultural writing.

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