Aging and Cleaning Porous Pots
The crusty or mossy buildup on clay pots as they age can be viewed two
ways. Either you find it attractive and you would like to encourage
it ·or you don't like it and want to know how to avoid or remove
it. Terra cotta clay and cement containers vary greatly as to how
smooth or coarse the surface is. The smoother, finer clay or cement
tends more toward the white crustiness while coarser surfaces are
best for a mossy buildup.
White, Crusty Buildup
The white markings that develop are a buildup of calcium salt. Most
city water in our area is very high in calcium, so these markings
develop naturally with time. As water passes through the porous clay,
the calcium deposits are left behind. Salts from water-soluble fertilizers
such as Miracle Gro or Bachman's Excel Gro will contribute to the
deposits too.
To remove the white salt crust from a clay/concrete container:
The way to remove the calcium salt buildup on clay is to soak the
container in a vinegar-water solution (1 cup vinegar/gallon water)
for a few days and then scrub it with a stiff brush.
Moss Buildup
It is often difficult to keep moss growing on a clay container since
the plants growing in the container tend to want more sun than the
moss, but even when the moss dries, it can still be attractive on
the pot.
To encourage moss to grow on clay/concrete containers: Brush
the outside of your container with buttermilk and place it somewhere
shady and humid. Mist it several times a day. At room temperatures
(or warmer), this usually results in a green patina within a few weeks.
If necessary, reapply the buttermilk every few days.
If you have a piece of live moss from your garden or stepping stones,
simply put it into the blender with a little water to make a thin
slurry. Paint the slurry onto the outside of a clay container. Keep
it damp, warm and shady for a few weeks and the moss will grow. Optional:
Add modeling clay to your thin slurry of moss and smear it on the
container. The clay makes the moss stick better and doesn't affect
the moss growth.
To remove the moss buildup on clay/concrete containers: When possible,
place the container in the sun to dry for a few days. Most of the
moss will have dried and can be removed with a stiff brush. If the
container is planted and you can't leave it in the sun for a few days,
carefully scrub the mossy areas with dry salt as an abrasive and rinse
it off. Keep in mind salt is a herbicide and shouldn't get on the
plants in the container, into the soil or on plants nearby.
© Bachman's 1996
Author: Margaret Purcell, Senior Horticulturist |
