Re: [IGSROBIN] Ceramic vs Plastic Pots
Last year I experimented with a dozen plants, all of roughly equal size and
planted in the same soil mix (1 part perlite, 2 parts Supersoil, 1 part
Kelloggs Amend). I put 2 in white plastic pots, 2 in dark plastic pots, 2
directly into clay pots, 2 directly in clay pots with some type of glaze
inside, 2 in white plastic double potted into a clay pot, and 2 in dark
plastic pots double potted into clay. I kept them in the same pots for about
3 months and kept an eye on them to see what developed, and I found:
The plants in white plastic pots developed a sort of green algae or mold on
the outer edges of the root ball, and the roots did not extend completely to
the edge of the root ball. The pots seemed to reflect some of the sun's rays,
but they also deteriorated with sun damage the most quickly and turned a very
unappealing yellowish color.
The plants in the green plastic pots did not have the green algae, but they
were even further back in the root ball because the pots got even hotter in
Those potted directly into clay took approximately 1/3 more water than those
in plastic. The clay pots also were very hot on the outside to the touch and
retained that heat for a prolonged period after the sun went down, and they
were very inconvenient to move because of their weight. They looked really
good though. I have to admit that I prefer the look of a clay pot to anything
Plants potted into a glazed clay needed a little less water than the clay
pots, but more than the plastic. They also were very heavy and retained heat
for a long time after the sun went down.
One factor that I hadn't considered came to the front when the neighbor's dog
lunged into the fence against which my plants were on the shelving unit, and
the entire structure hit the ground. Every clay pot burst into shards and the
labels flew out and it was a real mess. About half of the plastic pots hit
the ground and cracked, but they didn't split open, and I was able to pick up
the plant with most of its root system intact and repot them with minimal
problems. The ones that had been put directly into clay had a lot more damage
to work around.
Both the white and green pots placed inside clay pots did better than anything
else. I have resorted to putting some rocks in the bottom of the pot to help
weight it down, and in some instances, I use a bolt to secure the pot to the
surface, and then put the plastic pot inside. The plants required less water
than those put in plain plastic pots, and the roots go all the way to the edge
of the root ball because the pots stay cool inside the protective clay shell.
In Santa Anas, I have resorted to filling the gap between the clay and plastic
pots with perlite and sprinkling everything and throwing up heavier shadecloth
until the winds die down. When the winds are done, I dump the used perlite
back into the bin and use it in planting mix later.
If I'm taking the plants to show, I take out the plant in its plastic pot and
wipe it down with a little brush and I'm all set. Since the San Diego show
isn't judged, I take along the clay pots as well and just reassemble the units
in the display.
As an aside, because the pot is protected, I also have a typed label on the
pot under a protective mylar covering indicating the cultivar name in case the
label gets removed or broken in transit.