| People sometimes ask
"What water should I use for my orchids?" Like
most orchid-related things, "it depends" - mostly on the plants.
Some plants are tolerant of pretty much any water supply, while others
are very sensitive to water quality, particularly pH and dissolved
solids.
Unfortunately, folks often mistake the true meaning of water
descriptions, so let's look at them closer, adding some use criteria.
 | Pure water is defined (for our
purposes) as having essentially no dissolved minerals. It can be
obtained in a number of ways, each having its own pluses and minuses: |
- Deionized (DI) water has been
passed through a bed of various organic resins that extract the
dissolved mineral ions. If size properly, these can be
"on-demand" systems (installed in-line with your plumbing), but tend
to be expensive, as the resin beds need to be recharged or replaced
periodically.
- Reverse Osmosis (RO) achieves the
same result, but does so by passing the water through a membrane
having pores so small that they can only pass water molecules, blocking the flow of those dissolved ions.
RO systems are relatively inexpensive (purchase price of a few
hundred dollars at the most, plus low cost component replacement) in
terms of price per gallon, but tend not to be on-demand types, as
household units typically only deliver a few ounces per minute or
pure water, necessitating some sort of storage tank for periodic
uses of larger volumes of water.
- Distilled water uses an
energy source to cause the water to evaporate, leaving the solids
behind, then cools and condenses that pure water for use.
Unless you have a "solar still", these are costly, and in any
case will also require storage containers.
- Collected Rainwater or
Melted Snow are really
nothing more than water that has been distilled by nature. As
such it is free, but again, requires storage volume. Relying
on nature to provide your water supply is not particularly reliable
in many places.
- Air Conditioner or Dehumidifier
Condensate is again, a "distilled" source, but instead of
waiting for nature to condense the moisture from the air, we use a
refrigerant to chill the air and force the condensation. This
is a limited-volume source that is best utilized in warm, humid
climates, but still needs tanks to store it, as most units only
produce a trickle.
A note about collected rainwater or melted snow, or A/C condensate: where
you live (industrial/urban/rural) can affect the quality of the water,
due to air pollutants. You should also be aware that your roof,
being a place for airborne "crud" to settle, can contaminate the water
at the start of rainfall, and new shingles can release organic
chemicals into that water, as well.
| Purified water can vary
greatly in its chemistry, but is most often simply passed through
filters to remove sediment and dissolved organic compounds. No
minerals are removed from the water. A Brita filter is in this
category. This is an on-demand source, and doesn't cost
all tham much, but is of limited value.
|
| Softened water has been passed
through a chamber in which sodium chloride dissolves in the water,
forcing the ions of calcium, magnesium, and iron to precipitate, or
settle out of solution. Do not use such softened water on your
plants, as the sodium can be toxic to them.
|
| Spring water is just that - water
that has been drawn from the underground aquifer and bottled for
distribution. While it is lovely for drinking, it usually contains
plenty of dissolved minerals, making it taste great, but offering no advantage for
orchid growing. The same is true of well
water, as it's the same stuff, just pumped locally, rather than
bottled. If you're purchasing it in bottles, the cost is too high
to compete with most well- or tap waters.
|
| Tap water will vary all over the
map - literally. It can come from wells, rivers, rain and snow
melt runoff, any number of sources. In some places - the
southwestern part of the US, for example - the water is so mineral-laden
and alkaline, that it is virtually unusable for watering, as-is. In New
York City, on the other hand, the tap water is so mineral-free that
growers should use fertilizers that provide essentially all of
the needed nutrients, as the water brings essentially nothing with it.
Fortunately, your municipality can often provide you with a water
quality report, and while the actual chemistry may vary a bit during the
year, it ought to give you a good idea as to what you're getting.
The costs of tap water vary quite a bit as well, but at least it's
usually readily available. |
We like the idea of using pure water for all of our orchids, as by starting with that chemical "blank slate", and adding a
fertilizer designed specifically to provide the minerals in the correct
proportions at the proper pH (the Greencare Orchid Special for RO), we know
exactly what our plants are getting, so can manage their nutrition
precisely, and adjust in a controlled manner as needed. Our plants have
responded by growing larger, having more leaves, and blooming better than ever.
There is an additional benefit if you mist for humidification or cooling.
Dissolved minerals in the water can
leave a buildup on your plants' leaves. Misting with pure water avoids
that altogether, and you'll see that your plants really take on a glossy, clean
appearance.
Unless you live in New York City or where the water supply is primarily snow
melt captured in reservoirs, and if you're a serious hobbyist, you will probably
find that adding an RO system to your existing water supply is the best way to
go, as in the long run, the cost is a fraction of a penny per gallon.
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