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Common sense? Rich explodes some common
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water gardening myths --
Not Necessarily So!
by Rich Sacher, New Orleans, LA USA
It constantly surprises me that there is so much misinformation
on water gardening floating around, in spite of so many reliable
resources in books and on the internet. Some of these misconceptions
actually masquerade as "common sense"
in my ample experience, does not exist. Otherwise, very few of
us would ever make mistakes!
While some may object to this assertion, deep down, you know
I am right. Although it is impossible to enumerate all the follies
into which a water gardener may plunge, I list here some of the
more common ones, in the hope that you will avoid them, and instead
make highly original and noteworthy mistakes that none of us
know about yet. (Yes, you MUST tell us when you do!)
1) I should build my pond in that low spot
in the garden, where it is always wet anyway.
Please, don't! If the pond is at the lowest ground level,
heavy rains will wash chemicals and lawn debris into the pond
and your fish may end up swimming in your lawn. Also, if you
have a high water table, the liner will bulge to the top of the
pond with every heavy rain, looking like a whale about to break
If you have already made this error, be prepared to skim debris
off the pond after every heavy rain, and go in search of escaped
fish. Keep several large, flat, heavy stones nearby to place
on the bulging liner until the water under the liner has subsided.
Then top off the pond to replace the water displaced by your
"whale". For your penance, tell every prospective ponder
NOT to build their pond in the lowest part of their property!
2) My garden is shady, so I cannot have a
Yes, you can! Although you may not be able to grow waterlilies,
there are dozens of shade loving plants that can be used to create
a wonderful water garden, in a wide range of sizes, foliage types
and colors. Use blooming aquatics like Spathiphyllum,
white calla lily (Zantedeschia aethiopica), lizard's tail
(Saururus cernuus), and pickerel rush (Pontederia cordata),
all of which bloom in the shade. Consult the internet for more
shade loving aquatics. You can have a truly beautiful water garden,
even in the shade. And no, you cannot expect a night blooming
lily to bloom for you in the shade
it needs as much sun
as a day bloomer!
3) I need pots without holes in them, to plant
my lilies and bog plants. This will keep soil from getting out
of the pot and into the pond.
If you believe this, welcome to the common sense crowd
and most of the water gardening industry as well. In the United
States, an entire line of pots without holes have been created
for our use in ponds. This is not good. Almost all aquatic plants
grow better in pots that have some holes or slits near the bottom
of the pot. This allows for the passage of water (and oxygen)
throughout the rooting medium, allowing healthy roots to fill
the entire pot. In pots without holes, it is common to have a
dead zone several inches deep at the bottom where no roots can
live. It is wasted soil and may slow or stunt the growth of the
Ordinary plastic nursery pots with holes at the bottom can
be used for aquatics by placing some paper inside the pot at
each hole to hold in the soil. If you already have pots without
holes, make five or six one-inch slits in the sides of the pot,
near the bottom. Soil will not be able to get out but water and
oxygen will get in. You and your plants will be happy.
While we are talking about keeping the soil from escaping
into the pond, we need to know that placing sand or small gravel
on the surface of the soil WILL NOT prevent fish from digging
in the pot and making a mess. I don't care how many books tell
you to do this
don't! Your fish are already bored and
they have nothing better to do than play ping-pong with your
gravel all day long.
Large stones or pieces of slate may be needed to prevent fish
from foraging in your submerged potted plants, especially if
your fish are on the large side. As a bonus, when you lift a
stone to push a fertilizer tablet into the soil, replacing the
stone on top of the tablet serves to keep the fish from digging
it up. They LOVE the stuff, and although most fish suffer from
this substance abuse problem, they will not be harmed by ingesting
your fertilizer tablet. They may, however, uproot your plants
in the process. So stone your plants and starve your fish.
4) The books all say I need clay soil to grow
my waterlilies and bog plants.
As we are apt to say in New Orleans, au contraire, mon cher!
While it is true that some clay content in the soil is helpful
in retaining the nutrients you apply, it is not a requirement.
A sandy soil is fine for growing waterlilies and other aquatics
as long as you fertilize more frequently to make up for
the fact that the dissolving fertilizer tends to leach out of
the sandy soil more quickly than it does from a clay soil. This
is an example of how a mere recommendation (for some clay in
the soil) has somehow morphed into an absolute necessity. Not
so! As long as your local soil is not full of bark, peat moss
or other floating matter, it may be just fine for growing aquatic
plants, as long as fertility levels are maintained.
5) I need to keep my pond water at a certain
pH so my fish are happy.
Let us forgo the philosophical question of whether fish are
capable of happiness and go right to the pH of the matter
which is that most goldfish can tolerate a wide range of pH,
from 6.8 to 8.0, and seem to do just fine. Above 7.5, most pond
water may have enough dissolved nitrogen in it to turn the water
green with algae. This may make YOU unhappy but I doubt the fish
notice it. If your pond water is clear, and the fish are swimming
around with all their fins extended, and your lilies and bog
plants are thriving
why would you want to raise or lower
the pH? Control the pH naturally by keeping lots of underwater
grasses in the pond, by not using concrete blocks as pedestals
for statuary, and by not overfeeding your fish.
In fact, goldfish in a well-planted pond never need to be
fed at all
there is plenty for them to graze on. Koi,
on the other hand, demand daily feeding during the growing season,
and often require a biological filter to help remove their wastes.
A pond with overfed, overcrowded Koi may indeed have a pH that
is too high; but adjusting the pH with chemicals treats the symptom,
not the problem.
Some books on pond fish recommend putting some salt in the
pond as a "tonic" for goldfish. A customer did this
to his pond, and although his fish did not appear any happier
after being salted
the plants were visibly unhappy and died.
Although I have many signs posted around our nursery saying "Do
not put chemicals in your pond", this customer insisted
I was to blame because I did not post signs saying not to put
salt in the pond. I suppose sodium chloride is not a chemical
6) I need to cover the bottom of my pond with
pebbles, to protect the liner and to provide substrate for beneficial
There has been an ongoing debate on this relatively new practice.
Take it from me! The disadvantages of doing this are huge, the
benefits small. First of all, the underwater liner does not need
to be protected from the sun. It has a UV filter in it, and besides,
a thin layer of silt quickly covers the bottom of the pond. Second,
while it is true that the gravel will provide surface area for
the growth of beneficial bacteria, the liner itself will do the
same thing. Third, the gravel is slippery to walk on when you
are maintaining the pond. Fourth, and most importantly, silt
and debris will accumulate in the gravel, making it very difficult
to do an annual pond cleaning.
Do you have a pond with a good slope at the bottom, ending
with a large subsurface drain? If so, you can get away with gravel
in the pond. For your annual cleaning, use a high pressure hose
to blast all the silt and debris from the gravel, and wash it
all down the drain. Still, this will take hours longer than just
pumping out and rinsing the same size pond with NO gravel and
no drain on the bottom. I am confident that 98% of ponders do
not have a bottom drain installed in their pond liner
something that is usually found only in very large installations.
So, the only reason for gravel on the bottom of a pond is so
the installer can sell you the gravel. There ought to be a law
Returning to my previous assertion that common sense does not
exist, I leave you with the story of an irate customer who returned
a completely dead waterlily only two days after she bought it.
She had planted it in her garden, watered it well
died the next day. This story, like ALL my stories, is true.
I rest my case.