I have long wanted to try my hand at making the lovely and rustic hypertufa planters. After reading yet another blog post about it, I finally decided that yes, this is something I can do.
First, you'll need the following supplies:
1. Portland cement
3. Peat moss
You'll be mixing equal parts of all three ingredients with water, so plan accordingly when you make your trip to Home Depot.
It's also quite handy to have a garden hose near by. You really want to be making your hypertufa in the shade, so a garage is a pretty good spot.
Don't make the mistake I did when I didn't purchase actual Portland cement. I bought a bag of some other kind of mix that had lots of gravel in it. I went ahead and used it, but it mostly fell apart. You really do need Portland cement, which is a very fine powder which you will be tamping and firming down for good adhesion.
Now for the fun part....finding the right containers. I rummaged around my home, from basement to attic, and found quite a few containers that I thought would work. You want to steer clear of glass or metal, which won't be easy to remove from the dried cement. The best things to use are plastic or cardboard. These are somewhat bendable and aid in the mold removal process.
Here are some of my containers. I sacrified an old hat box as well as a plastic popcorn bowl I got for free from Orville Redenbacher for eating a lot of popcorn. If you don't have much around the house, a dollar store is a great place to rummage. Avoid using any container that has a lip around the top edge, as this will be an impediment to removing your mold.
The trick is to find a smaller container that fits well inside a larger container. Remember that you will be filling the space between the two containers with cement. Ideally, the gap between the containers should be at least 3/4" to as much as 2 inches wide. The larger the container, the larger the gap.
Before you do anything, put on a face mask and wear rubber gloves!! Mix equal parts of the Portland cement, perlite and peat moss. Use your hands to carefully mix the dry ingredients together. Then add water, a little at a time, and mix well until it resembles cottage cheese. You want everything well blended, but not soaking wet. Too much water weakens the strength of the pot.
Be sure to use a cooking spray like Pam to coat all sides of the larger and smaller containers that will be in contact with the concrete. This will facilitate mold removal.
When your cement is well mixed, begin using a trowel (I used my gloved hands) to pour a layer on the bottom of the larger container of about one inch thick. Tamp it down firmly. Then place your small container inside the larger one. It's a good idea to fill it with sand or a brick or maybe a few rocks to help steady it as you fill around it. Press the cement down firmly and level off the top as best you can. A small block of wood works well for this.
Here's what mine looked like, filled and ready to dry.
Put the containers in a shady spot and wrap them with plastic. They should be allowed to dry for at least 24 hours, or maybe 36. After that period of time, test dryness by trying to scrape the edge of a pot with your fingernail. If you can easily scrape off some cement, it needs more drying time.
When you've determined it's dry enough, remove the inner container. Gently bend it if it's plastic. Then remove the larger container, carefully. Now the pot needs to cure for a good three weeks.
After that, you'll want to put it outside and keep filling it with water for about a week. This will help leach out excess lime that could otherwise harm your plants.
That's pretty much all I've learned about making hypertufa. In the first batch that I made, two of the five pots were no good because I used the wrong kind of cement, as mentioned earlier. And I could see that I hadn't really tamped down the concerete well enough, allowing a pebbly surface to remain, and this just fell off the pot when it dried.
Here's what my first three pots look like, still curing:
OK, not exactly what I had in mind. My mistake, I think, was in not really tamping down the top edge of the pots; that's why they look all crumbly. I worked a little on them with a stiff wire brush to try to smooth them out. The idea is to make them look like they've been around for a hundred years, and with these you could see a somewhat artificial looking lip around the top of the pots. But I'll be working on them. They were still a little too friable when I brushed them before.
I know they don't look like much now, but try to picture them with a few nice succulents, nestled in little spots through the garden. I can't wait!
In other news, here's an old colander my mother was going to throw away. I lined it with burlap and made another planter with it.