If you have
ever had a dirt-planted pot of plants tip over in your
pond, you know first hand what a mess it is to clean up.
Once the dirt from the pot gets into the pond, the pump
further spreads the dirt throughout the entire system.
Even when a pot does not tip over, the water still has a
brown tinge to it that people often refer to as tea
colored water.
Over the years we had experimented with different
planting methods using different types of planting media
and still the water would take on a brown tinge once we
placed the plants in the pond. Additionally, there was
that dreaded, stinky smell at re-potting time.
Every year,
I dreaded un-potting the stinky, smelly pot full of
dirt. Dirt will go anaerobic in just a year in the pond
and send off hydrogen gas (rotten egg smell). The
hydrogen gas can actually build up in the dirt to the
point it will kill pond fish.
Over time, generally a year, the dirt will mix with
organic waste like fish feces, uneaten food, and pieces
of plants. As the organic material builds up and
decomposes, the much needed oxygen cannot reach the
roots, and decay takes place. The decaying organic
matter produces ammonia and carbon dioxide, which use up
the oxygen the pond fish need to live!
The accumulation of this rotting matter also encourages
the buildup of anaerobic bacteria, which are bacteria
that do not need oxygen to survive. These bacteria are
responsible for the nasty smells and are often the cause
of health problems in pond fish.
We have been
growing pond plants that we sell hydroponically for many
years in the greenhouse and I was fairly sure that there
had to be a way to grow them in the pond without dirt.
My first experiment was growing plants in my streambed
without dirt. Streambeds are always a source of algae.
By reducing the amount of sunlight that hit the rocks, I
thought I could cut down on the algae growing on the
rocks if I could provide shade on the rocks.
Watercress growing in our streambed in just a few inches
of water. The bare root plants were wedged between the
rocks.
We placed
bare-root plants in the streambed by moving a couple of
rocks aside. Using the rocks, we propped up the plants
until the roots could take hold. It worked very well! We
have tried this method with other plants including
Egyptian Papyrus, Cannas, taros, bluebells, bog lily,
King Tut papyrus, and many different water-variety
hibiscus.
We tried low
growing plants like pennywort, lemon bacopa, water mint,
parrots feather, and watercress; they worked just as
well. These are just a few, there are others that will
work just as well.
At first, we
tried growing bog plants in black nursery pots with pea
gravel. Then the following year we noticed they were
just as smelly as those we had grown in dirt in previous
years.
The following year, about 6 years ago, we decided to try
using just the black nursery pots and large rocks.
Egyptian Papyrus in our streambed growing bare root in a
few inches of water. At the base on the right side there
is watercress. I should note the 2 above photos were
two different years. I love the watercress because if
it gets to big and outgrows its space, I shear it off
and feed it to my koi. They love it!
It was
amazing! In just a few weeks, the roots were growing all
around the rocks. The plants were bigger and fuller than
ever before. Tall plants like the Egyptian papyrus,
large growing umbrella, cannas, and hibiscus did not tip
over in the pond anymore; this is because the rocks were
large enough to weigh down the plants so the wind would
not blow them over.
Using the our soil-less method one does not need to
worry about fertilizing because the roots will grow out
of the drainage holes in the pot and use the nutrients
from the fish waste in the water!
One other
bonus, if you live where the winter is cold, is that you
can easily move the plants into your home for the
winter. Purchase a large tote-storage type container.
You can place several plants in the same container near
a sunny window in your home for the winter. You no
longer need to drop the plants to the bottom of the pond
for the winter unless you choose to do so.
Above is Iris growing in the rocks in our streambed.
Right picture a few weeks later when the iris started to
bloom.
Lower pond plants on plant shelf in plant stands, all
growing soil-less in 3 gallon pots filled with rocks.
These are all bog plants and the top of the pot is even
with the water.
Above: Roots growing out of the pot of Hibiscus.
Lilies
We tried the soil-less method above on both hardy and
tropical lilies, but growth was not successful. In many
cases, they just died. We then experimented with growing
them in sand.
Sand will go anaerobic in time, but not as fast as dirt.
We use 3-gallon buckets with metal handles that we
bought at dollar type stores. The handles make adding
the buckets to and removing the buckets from the pond
much easier.
By planting in a 3-gallon bucket, we only need to remove
the lilies every 3 years to divide them. The bonus is
the sand is very easy to wash off the tuber and roots.
We replace with clean sand at that time.
Lotus
We also found large round tubs at a dollar store and the
tubs are perfect for lotus tubers. We have been growing
our lotus in sand for about 5 years now.
Fertilizing in Sand
Sand does not contain, nor does it hold many nutrients.
You need to fertilize the lilies and lotus regularly,
about ever 3 weeks with pond-plant fertilizer tablets.
Simply push the tablets down in the sand around the
outside edge of the container, using 3 for every gallon
of sand.
