If you haven’t already, I highly recommend taking a Saturday morning class at The Garden Spot. Many classes are free, offering information and inspiration. My inspiration always seems to be attached to a receipt; I have trouble exhibiting restraint in that place! In early March, I went to learn what hypertufa was all about. First – what it’s not: natural tufa is a slow naturally occurring process, causing limestone rock to become a porous and happy environment for plants. Natural tufa was used for stone sinks and animal troughs in Great Britain, so I’ve read. Hypertufa is intended as a substitute for natural tufa (now rare and expensive). Hypertufa pots are lightweight in comparison to terra cotta and concrete and can withstand temperatures of -20 degrees Fahrenheit (that’s us, Whatcom County). For $35 all supplies were included in the class fee. I’m pleased to report that all of the ingredients are inexpensive and readily available. I’ve seen many hypertufa recipes, but here’s how it shakes out:
Hypertufa = 2 parts peat moss, 1 part Portland cement, 1 part sand
This ratio is the most important part of the process. Use any size container to measure out the dry ingredients. After that, it’s akin to childhood mud pie making. Armed with basic knowledge and newly acquired hands-on technique, I decided to make more. I gathered my recipe ingredients on a late night trip to a big box store (to remain unnamed). I managed to slide an entire 90 pound bag of Portland cement into the shopping cart all by my lonesome! All pride was immediately squelched when I tried to dead lift my weighty purchase in the hatchback. After many futile attempts I had to call Joel for a rescue. Driving up to my aid, he said he saw smoke coming out of my ears. Oh well, now I have a lifetime supply of Portland cement.
I plan to share the hypertufa love, so I made up a large batch and divided it into several gallon zip lock bags.
Ready to get your hands dirty? Just add water – I’ll show you how!
Wearing protective gloves, mix the dry ingredients in a large plastic container (preferably one that’s easy to rinse), breaking up any chunks of cement and peat moss. Wear a mask if you get ferocious – don’t want the black lung.
Add 1 part water (in the same container you used to measure the dry ingredients) and mix until moist.
Mixing hypertufa is like mixing pie crust; slowly add water to obtain a crumbly consistency. Grab a fistful of the mixture and squeeze (hard!). If you see a small amount of water gush out your gloved fingers, you’re there. Technical huh?!
Line your mold (I chose a round bowl shape) with plastic. Folds in the plastic will ultimately be a good thing, adding texture to the finished product.
Place mixture in the mold and firm to form the bottom of the pot. For this size mold, aim for a base and wall thickness of 1-1 ½ inches. If you want to make larger structures, chicken wire reinforcement will be necessary. You can test the depth by poking a hole in the bottom as you go (this can later be used for a drainage hole) or filled in if you want a trough or birdbath.
Work to compact and smooth the mixture as you move up the sides of the mold to your desired height. Round the top edges to reduce the chance of chipping and breaking. When satisfied, put your hypertufa in a garbage bag and prepare for a slow cure.
Curing: The ideal curing environment is 2 weeks at 55 degrees. Occasionally mist the hypertufa with water – it slows down the cure and strengthens the material. As it dries, the hypertufa will become lighter in weight and in color. After 2 weeks, remove from the mold. You can give the pot a more distressed look by accentuating the lines left by the plastic by scraping with a screwdriver.
After curing completely, let the hypertufa sit in the rain or mist often with water, allowing the alkalinity of the Portland cement to leach out. Finally, before planting, rinse the hypertufa with a ¼ cup vinegar in 1 gallon of water. Enhance mold growth and that lovely Martha patina by applying buttermilk mixed with moss or 2 sugar cubes mixed with a beer and pulverized moss. Then drink a beer and admire your work!
And another photo for good measure. A very healthy looking Valerian, that was just a wee lad last season.