Karen Gilliam, WSU - Whatcom County Master Gardener

Old Stone sinks and animal troughs have been used to grow plants for many years. Now they are scarce and very expensive. So, we can make them from hypertufa Hypertufa is an artificial medium with absorbent properties similar to tufa rock. It is lighter than regular concrete, and will not be damaged by freezing after it is completely cured.

Materials Tools

Peat moss
Portland cement
Sand, vermiculite or perlite
Chicken wire for large pots - reinforcement

Rubber gloves - heavy
Respirator to protect from cement and peat moss dust
Plastic, bags or sheet up to 4 mils thick
Pot or tub for form
Pots for feet forms
Mixing tub or wheelbarrow
Wire Brush
Wooden dowel 1/2"-3/4"



Peat moss- 2parts, Sift through finger to remove all lumps
Portland cement - 1 part
Sand, vermiculite, or perlite - 1 part

mixing ingredients
Figure 1


working mixture
Figure 2


forming pot
Figure 3


Mix the above ingredients dry with your hands until completely homogenous. Add one part water and mix well. Add additional water if needed to make a mixture that is just moist. (Figure 1)

If worked in your hand the water should just be visible between the fingers when a handful is firmly squeezed. (Figure 2)

Use chosen mold. (We used a 2 gallon black plastic pot.) Line with plastic (a grocery store bag used here) for easy removal from mold. (Figure 3)

Place enough concrete mixture in bottom of mold to cover about 1" to 1½" deep for small pots. For drainage hole cut a ½" dowel to selected depth (1 - 1½and insert into center of pot. Firm the cement mixture even with the top of the plug for correct thickness.

Add mixture and work up the side of the mold, one hand on the outside of mold, one on the inside. Work until air is expressed and sides are smooth. At this point check for uniformity of thickness in the sides (about 1" for this size). Recheck smoothness of bottom. Work to compact and smooth. Build to desired height.

Using fingers and pulling plastic tightly mold top edge to round edges. Sharp edges can easily be chipped or broken so by rounding edges you have a more durable pot. When pot is at desired height fold plastic tightly to inside of pot. If the bag is not large enough, use 2nd bag to cover inside of pot. Then it is time for a slow cure. One week in warm weather, 2 weeks at 50F. Keep from freezing. At least 55F is best. Concrete cures with the presence of water. If possible spray your bowl with water often, (several times a day). This is especially important in dry climates to strengthen the final product and prevent cracking.

After this cures, remove your pot from the mold and take off plastic. Be careful, pot is not very strong and is rather crumbly at this point.

Remove dowel from drainage hole.

Any sharp edges can be shaved and smoothed as desired. The drain hole should be checked and smoothed.To give the pot a more natural appearance, accentuate the lines left by the plastic with a screwdriver or other sharp tool. Brush the outside of the pot with a wire brush to roughen and make grooves for the algae and moss to grow.

Let cure for another 2 weeks, and then leach for 5-10 days. Let them sit in the rain or spray often with water to leach out some of the alkalinity. Do not let freeze during this process.

Rinse with vinegar solution to neutralize before planting. Use ¼ cup vinegar to 1 gallon water. Immerse if possible for about ½ hour. Let drain.

Happy Planting! These pots are very porous. Great for rock garden plants, succulents, grasses, and bonsai. Note: This pot will continue to cure and get stronger as it's used. In the presence of water the concrete will cure for many years.

Remove pot from mold
Figure 4


Hypertufa Final Product
Completed Pot!


Paint with one of the following solutions to enhance moss and algae growth.



To make a birdbath the hypertufa should be about 3" thick. It is porous, so to make it hold water have one person pour hot liquid paraffin around the basin. The 2nd person smears the wax around wearing heavy rubber gloves.



To make very large pots or tubs use chicken wire reinforcement in-between two layers of the hypertufa mixture.

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