Hypertufa looks like concrete, but it is much lighter and can take a knock. I think hypertufa looks nicer than plastic.
Making your own pots out of hypertufa is a fun project you can do over the winter. Concrete is made with cement, sand, and gravel. When you make hypertufa, you change the recipe and use light ingredients such as peat moss instead of the sand and gravel, which gives you something that looks a bit like concrete or stone, but is lighter.
Other common ingredients are things that you find in potting soils, like perlite and vermiculite. If you search online, you will find tons of recipes. I like this recipe because it is really easy — we just mix cement with the potting soil we have on hand!
Like with concrete, you can build a wooden frame that you fill with the wet hypertufa mix. Once it has dried, you remove the frame. We did this once, but it is a lot of work to make a frame. You need to make both an outer frame and an inner frame. An easier way to make hypertufa containers is to use two pots. Use the larger pot for the outside form and the smaller pot for the inside.
- 2 clean plant pots, one small enough to fit inside the other (We used a 13-inch pot and a 12-inch one.)
- Cooking spray (or some cooking oil and an old paintbrush)
- A large container and tools for mixing (We used our old wheelbarrow and a couple of shovels.)
- A bucket or other container for measuring
- 1 part peat-based potting soil (The potting soil we used also had perlite, which looks like little white balls. It’s actually bits of volcanic rock.)
- 1 part Portland cement
- Rubber gloves (NOTE: Wet cement irritates the skin, so wear these!)
Spray the parts of the pots that the hypertufa will touch with cooking spray (or brush with cooking oil). This prevents sticking and makes it easier to slide the molded hypertufa out of the pots once it is dry. Mix together the potting soil and Portland cement.
Add enough water so that the mixture is completely wet, but not soupy. Put about 1 inch of hypertufa at the bottom of the larger pot. This makes the bottom of your hypertufa pot.
Put the smaller pot on top of the layer of hypertufa, and center it so that there is an equal space all around the sides. Now start to fill up that space with your hypertufa mix with a trowel, adding a bit at a time. The idea is to make sure there are no big air pockets. But you don’t want to pack it down too much, or the mix will be too dense.
Fill to the top of the pots and smooth out the edge. Cover the whole setup with a sheet of plastic and put it in a dry, shady spot. Wash out the container and tools you used to mix your hypertufa quickly, before it dries onto them.
Let the hypertufa sit in the pots for at least a week. It will feel hard after a day or two, but it gets stronger the longer it sits, and the color gets a bit lighter. When it’s ready, peel the inner pot away from the sides and pull it out.
Turn the larger pot over and push gently from the bottom. Your new hypertufa pot should slide right out! Drill a hole in the bottom for drainage, and you are all set to plant.
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Excerpted from Gardening with Emma: Grow and Have Fun: A Kid-to-Kid Guide by © Emma Biggs and Steven Biggs, photography by © Donna Griffith, used with permission from Storey Publishing.