Bonsai pots and trays are more than just a frame for a picture. They are a fundamental part of the composition. However, sometimes you can’t find an appropriate pot for bonsai design or maybe need a larger pot but are reluctant pay the price. This is particularly true for grove and forest bonsai.

If you don’t mind a rustic container, then home made tufa might be your answer. While there are different material formulas for tufa, they share the common usage of peat moss and Portland cement.

Trisha & Rocky making a hillside pot
Phil dry mixing the ingredients

At the Sunset Bonsai Club tufa workshops, we used one part filtered peat moss, one part Portland cement and one part sand.

Another club's formula consist of 2 parts Portland cement, one part filtered peat moss and one part small vermiculite. And yet another calls for two parts Portland cement, three parts sifted peat, three parts perlite.

Whatever formula you settle on, they all require that you sift the peat moss through a screen, remove all debris and thoroughly mix the dry ingredients together. The peat moss acts as the bond fiber for the tufa and must be free of foreign objects.

After the ingredients are completely mixed in a wheel barrow, we slowly added water. Putting on rubber gloves, w e tested for the right consistency by squeezing a handful of the mixture. When we only got a few drops of water, then the batch was ready.

At this point, the mix was ready for either being packed into a mold or being spread out as a tray. Whether we made a pot or a tray, we poked holes into the wet tufa with corks, tubes, or dowels. Other club members added concrete coloring agents to the mix.

Trays were laid out and shaped on top pieces of plywood. We covered the top of the plywood with sheets of 6 ml plastic. To create interest around the edges, we rolled newspaper into balls and stuck them between the plywood and the plastic. Some members embedded rocks into the wet tufa. However, there is a tufa strength limit to larger trays and caution or reinforcing should be used when the tray is over three feet.

Pots can be formed using a variety of molds. If lined with plastic, a couple of cardboard boxes quickly make a simple mold. Old trashed plastic balls can be cut and shaped into a mold. For those with the right tools and skills, wood makes a great mold. Below are pictures of some of the steps in making a hillside bonsai and the results.

Start frame for hillside pot
Hillside pot after tufa applied
Finished hillside tufa pot

Generally, we make our tufa pots and trays in the summer so we can keep the messy process outside. For safe curing, we wrapped or placed our tufa inside large plastic bags and waited 2-3 weeks. If the tufa cures too fast, then cracks will occur and weaken the structure. Once removed from the plastic sack, we place the tufa outside in the elements and let them age over the fall and the winter. We believe this helps to leach out any harmful cement chemicals that might inhibit growth or poison plants.