Hypertufa (n.): An artificial and lightweight stone that gardeners can create from a recipe and mold into plant containers, troughs and any other shape.
If you mention hypertufa to a non-gardener, you would probably get a blank look. But in the gardening world, it is very trendy and a sign of a serious gardener is the number of hypertufas scattered in their garden.
Perfect for planting miniatures and alpine plants, hypertufa troughs fit into any size garden, large or small. A man-made imitation of light weight tufa rock, hypertufa is a mixture of 3 things: perlite, peat moss, and portland cement. Some fiberglass fibers used for strengthening is a good idea but not essential.
Purchasing a ready-made one is always an option but pricey. A medium 15″ trough could set you back around $75, whereas the materials for constructing several will be around $30. And the fun involved is something that pulls people together for a hypertufa party, complete with wine and lots of food.
Any Excuse for a Party!
Hypertufa partying takes some planning and preparation but is worth it once everything starts to happen. ‘Mise en place’- the cooking phrase, having everything in place, is paramount here. You don’t want to be running around gathering supplies while everyone is waiting and concrete is being mixed.
I tell my guests that I will provide all the materials for making if they bring a mold on a piece of plywood, a face mask, and rubber gloves. Molds are simply a tupperware bowl without a lip, an old styrofoam ice chest, cat litter container, or a sturdy box.
- Blue Tarps– I use a couple of blue throw away tarps to lay on the ground which makes cleanup a breeze
- Face Masks and Gloves– Face masks are essential to keep you from breathing portland cement dust which is toxic; Rubber gloves keep your hands clean
- Mixing Tub– I use an old cement mixing tub, but any wide mouthed plastic container will do
- Mixing Tools– Use a shovel or sturdy garden trowel
- Old Trash Bags– Using plastic between the container and the hypertufa mix when packed into the mold makes the unmolding process easy
- Plywood Pieces– The pieces when wet are heavy and hard to transport without a study board underneath it
- Portland Cement-one 96 pound bag which costs around $15; this will make lots of troughs, at least 12 good sized ones
- Peat moss– 3.8 cubic feet bag will cost around $16
- Perlite-one 4 cubic bag costs around $14
- Mesh Fibers– These cement fiberglass fibers are a strengthening agent for the hypertufa, available at cement suppliers or on line, a 1 pound bag at $7
You can get the perlite and the peat moss in smaller sizes if you just want to make a couple of troughs, but the Portland Cement only comes in the monster size.
Using a small bucket for measuring, use 3 parts portland cement to 2 parts each of the perlite and peat moss and mix these thoroughly into a mixing tub, breaking up lumps. Add the fibers at this point, if you are using them. I find if you add the fiberglass fibers your hypertufa is more resistant to cracking in the long run.
Enlist everyone at this stage in mixing and squeezing the lumps to make a uniform mix. Next have your hose handy and start adding water in increments, mixing after each addition until the mixture will hold in a clump in your hand. It resembles wet cottage cheese at this point.
Molding – The Fun Begins!
Molding and forming the trough is the fun part. Everyone brought their mold staged on a sturdy piece of plywood so that they can transport it home easily. We covered the molds with a piece of old trash bag which greatly simplifies the removal of the mold from the hypertufa. After donning their gloves, people dove into the tub and grabbed handfuls of the mixture and start covering their mold with a two-inch layer of hypertufa mixture. It is important to have good coverage so that the walls are sturdy and won’t cave in. I had dowels ready for people to insert through the bottom of the troughs for drainage holes.
A hypertufa made in a Styrofoam ice chest
After everyone had thoroughly coated their mold and smoothed the bottom and sides, we took a break and admired everyone’s creations. At that point, the troughs are ready for curing. Curing simply means that the cement has to dry slowly to avoid any cracks forming. To do this, simply mist the container once a day and cover the trough with a piece of plastic to hold in the moisture. You can’t rush this step and it will take a couple of weeks to fully harden and cure.
After waiting impatiently for about a month, you can turn the hypertufa over and remove the mold. At that time, you can fill it with soil and plant with succulents or miniature plants. Your completed trough will last for years outside and will eventually grow moss to make it look like an antique planter.