Hypertufa (pronounced hyper-toofa) is a man made, concrete like material that is light weight, yet surprisingly durable and versatile. It can be used to make planters, garden ornaments, sculptures or stepping stones.
This project is a good way to get acquainted with the medium. It’s pretty simple and the end result is an organically shaped sphere, which means you don’t have to worry about being perfect.
There are several different recipes for the hypertufa mix. The one I have provided here is a basic combination of Portland cement, peat and Perlite. Perlite is a potting soil amendment that looks like tiny styrofoam packing peanuts. It's very lightweight. You should be able to find it at your local garden center. Sand can be used if Perlite is not available. An online search of hypertufa will provide you with some other recipes and ideas. I encourage you to explore the possibilities.
Dust Mask (when mixing ingredients dust is caustic and damaging to the lungs)
Perlite (or sand)
Bucket or Bin for Mixing
Trowel or Scoop
Something to cradle the sphere while it cures such as a Box and newspaper or old nursery pots.
Select an area to make your hypertufa sphere that is open and well-ventilated but sheltered from breezes. Gusts of air will dry the mixture prematurely. I set up a work table in my garage and opened the garage door.
Cut a hole in the side of your rubber ball. It should be large enough to accommodate your trowel or scoop, but not so large that the ball won’t hold its shape when filled with hypertufa mix.
Mix 1 part Portland cement, 1.5 part peat and 1.5 part Perlite. If you are substituting sand for Perlite use 1 part Portland cement, 1 part peat and 1 part sand. Make sure everything is well blended and any large chunks of peat are broken up.
Slowly add enough water to moisten the mix. It should be the consistency of oatmeal or porridge.
Scoop the moist hypertufa into your prepared rubber ball.
The key to hypertufa’s durability is the curing process. To keep it from cracking it should be allowed to dry slowly. To keep the shape of the sphere while it cures, the balls need to be placed in a stand. I used old nursery pots, but a box stuffed with balled up newspaper would work nicely too.
After a month remove the sphere from the box. Peel or cut away the rubber ball. Wear rubber gloves when you do this, as the material may still irritate your skin.
Because it is a solid form, the hypertufa may not be completely dry so protect table surfaces if you bring your sphere indoors. Mine are out in the garden. They’ve become nicely weathered and mossy but have held up quite well. I even leave them outdoors during winter and they have not been damaged by freezing temperatures.