Hypertufa: Mold Stepping Stones and More in Your Garden
Hypertufa is the result of blending together varying amounts of Portland cement, sand, peat moss, perlite or vermiculite, and water to form a mud-like mixture that hardens into a material similar to that of stone, only it’s much lighter. This mixture is extremely versatile; you can sculpt it with your hands or mold it using a form. Additionally, you can easily color it or add mosaic pieces and other objects, such as shells, to it. Hypertufa is perfect for making garden ornaments, planting troughs, sculptures, stepping stones, spheres, fake rocks, and many other objects for the garden. You can even make castings of various objects for use as birdbaths. Hypertufa is porous, making it ideal for use as planters. This material will resist cracking in freezing temperatures; and the natural elements, over time, will give it an aged appearance.
Molds can consist of nearly any item, some of which you may already have on hand. That means there’s no reason for running out and spending money on something you don’t need; improvise and use what you have available at home. This could be in the form of cardboard boxes, containers of any size, and various objects such as balls and wadded-up plastic bags. Shallow pans and boxes make excellent molds for stepping stones and birdbaths; while the deeper ones are great for planters. Beach balls or bowling balls can be used to create garden spheres. Wad up plastic bags to create textured rocks for lawn and border edging. Hypertufa bonds quickly to some objects; therefore, it’s a good idea to line molds with plastic wrap to help release the hypertufa from the mold. If you don’t have plastic wrap on hand, you could try some cooking oil/spray, Vaseline, or mineral oil instead. If you are using a clay or terra cotta pot as a mold, you should soak it overnight in water and coat afterward with mineral oil.
Hypertufa is easy to make; there are numerous recipes you can mix up depending on what you want to create. However, for your first time, you might want to start small until you get a feel for what you are doing. Stepping stones are a fun first-time project, and you tend to get better with each one as you go. The most basic recipe includes mixing 1 part premixed Portland cement and sand to 1 part peat moss and 1 part perlite. All of which can be purchased at most home and garden centers. Mix together in a wheelbarrow using a metal rake, adding water slowly. Continue adding water until the hypertufa mixture becomes nice and squishy but firm. Be careful not to add in too much water or your hypertufa will not hold together and will fall apart. Pour the mixture into the mold. If you are not making stepping stones, smooth the hypertufa mixture firmly into or outside of the mold. Try to keep it about 1 �½ inches thick. Add drainage holes in the bottom of planters before curing.
Place or cover the object with a plastic garbage bag or sheeting and seal tightly. This should be placed, preferably, in a sunny location for curing. The heat from the sun encourages condensation to take place in the plastic, keeping the hypertufa moist. If you have to keep your object in the shade, it will require occasional checking and spritzing with water. Leave the hypertufa object alone for about 3-5 days or until it becomes difficult to scratch off residue. Release the object from the mold at this point and reseal with plastic, leaving it for a week or more. The longer it cures, the better the results and the stronger the object. Remove the object from the plastic once it sounds hollow inside when tapped.
I have found it quite useful to perform hypertufa projects during the fall. This allows plenty of time for curing throughout winter. Once spring arrives, I have a wonderful piece of art to add to the garden that everyone can enjoy for many years to come.
