Hypertufa is a mixture of peat moss, cement and sand that you can sculpt and make into your own garden decor pieces and planter pots.
You can create statues, birdhouses, planter pots, stepping stones and more. The choices are limited only by your imagination.
For this project you will need some space, if you are limited in your own yard or only have a balcony then ask to borrow a friend’s yard or driveway.
Lay down a tarp first to keep the mess under control. Use a picnic table if there is one.
Before we even get into the recipe let’s talk about the finished shape you’d like to achieve, again this is limited only by your imagination and random items you might have on hand to make a mold with.
Make a Mold
You can use just about anything you are able to find around to create the mold. Another plant pot or bowl of any size inverted can be the inside size of the new sculpture that you want to make. Also, stroll through the dollar store and see what cheap plastic bowls, baskets or other “forms” that could be used.
To make planters that are large and rectangle you will need cardboard boxes of two different sizes. To make round one you’ll need two kitchen bowls of different sizes. One needs to be larger than the other but the same shape.
The vertical space between the box sides will become the sides of your hypertufa planter. You’ll be filling the bottom and the sides with the mixture and pressing it down to create a rectangle planter box.
The boxes can be any size but the larger the planter then the thicker the walls need to be for strength (use a smaller inner box).
**Don’t use a metal or wooden container unless you cover them in plastic first**
The hypertufa mixture won’t stick to cardboard, plastic or styrofoam so these are the best materials to use.
Make Some Feet
It’s pretty likely that the planter you make will have a flat bottom. You’ll need make little feet for it so air can flow underneath it and so water can drain out as well.
This is easy to do just take little bits of mixture and form them into four little rectangle blocks and let them cure like everything else you make.
These will sit under each corner of of the sculpture raising it up to allow air circulation and drainage.
It’s very important to cure these feet in the same way as the project itself or they won’t be strong enough to hold up the weight of the filled planter.
Basic Hypertufa Recipe
3 parts Portland cement (not pre-mixed concrete or mortar)
3 parts Fine grain sand
3 parts Sifted peat moss
Adding a small handful of synthetic concrete reinforcing fibers will increase it’s strength a lot.
First loosen and fluff the peat moss by rubbing it between your hands, discard any chunks or large pieces.
If you have a fine mesh sifter then you can use that to filter out the big bits. Mix these ingredients together in a wheelbarrow. Use enough water to bring it all together too the consistency of cottage cheese (like mud pies).
The amount of water needed will vary depending on how much mix you have and the humidity in the air. It is not an exact science, but it should stay in your hand when you pick it up and let out only a tiny bit of water when squeezed a little.
Wear rubber gloves throughout this process as the cement will irritate your skin and also wear a dust mask at least until your ingredients are thoroughly wet.
Curing Your Project
After you are done sculpting, the hypertufa has two stages of curing, the first happens after the first 36 hours in which the piece has to be covered in plastic.
The plastic makes the mixture cure more slowly and the slower the cure the stronger the resulting piece.
Test: After a couple of days scratch the side of it with your nail, and if it makes a mark then it’s too soft to move or work with.
Wait a little longer until you need a butter knife to scratch it. At this point carefully remove the mold, it’s still a bit soft inside though. Use a stiff wire brush to smooth the edges and corners.
Now put the piece aside again in a shady, dry spot to cure for another 3 weeks. The second stage can take up to a few weeks to completely dry and set, don’t rush it. After this time passes the planter will be lighter in weight and more pale in colour.
Rinsing Your Planters
All that’s left to do is the “rinsing” out of the hypertufa.
There is a high level of lime in the Portland Cement and that will be harmful to the plants. All you need to do is keep the container filled with water continuously for ten days, that’s it.
The hypertufa is porous and by doing this the water runs through and it will draw out the lime as it goes.
The containers will be naturally porous but (after rinsing out the lime) you can make a few extra holes in the bottom with a masonry drill bit to increase the water flow. Choose a small drill bit so the water can run out but not so big that the soil can get out.
Once the rinse and flush of the lime content is done then you are clear to fill it with soil and your favourite plants and enjoy the added beauty of your own creative art sculptures in the garden.
