There are many different hypertufa recipes on the internet and each individual works with a recipe that turns out for his or her own needs.
The recipes are nearly the same but one person may want a light recipe and another wants a heavy or strong one. You’ll need to experiment to find out what suits you. And I mean that in both weight and winter survival.
How Strong Is Hypertufa?
Here is Ohio in Zone 5, I need my hypertufa planters to be frost hardy and strong. I want them to survive winter after winter, without cracking, whether it goes to zero or 20 below. (Not to mention my precious plants inside the hypertufa.)
It needs to be mentioned that a wet/frozen planter is not going to survive as well as a dry/frozen planter.
So don’t situate your planter under an overhang where it will be drenched in each winter rain. Move it! and put it on a pedestal of bricks or rings so that it is not left sitting on the wet ground…or horror! In a puddle!
What is My Recipe for Hypertufa?
Here is one of my best recipes that I have used for years.
My next favorite recipe for an even stronger hypertufa planter:
1 part Peat Moss
1 part Perlite or Vermiculite
1 part Portland Cement
That second recipe is great for the hypertufa molds such as the ones for Easter Baskets, Pumpkins, Shamrocks, etc so that the shape is well defined.
Water – The Final Ingredient
The final ingredient is water and that is subject to your humidity. Add it slowly such as a half gallon at a time when you are using gallons as your parts, then keep stirring and mixing as you observe your mixture.
Use short handled garden hoe or trowel or just mix with a gloved hand.
Once it is mixed, leave it set for a short time so that all the water in the mix will be absorbed. When you come back in 5 minutes, mix again and add a little water if it needs it.
Rule of thumb is when you pick up a handful and squeeze, only a few drops should squeeze out between your fingers. But you do need to see those drops. Too dry and you’ll have a hard time molding it.