Maximum Yield USA December 2019 / January 2020 | Page 30

HARD
OR SOFT
H 2 O
Know what’s
best for your plants
When growing indoors we often hear about hard
water and soft water, but do you really know
what the difference between the two is? It’s
worthwhile to look at exactly what hard water
and soft water are, what their differing
components are, and what positive or
negative effects they have upon your
plants and equipment, and why.
by Rich Hamilton
30
Maximum Yield
Hard Water: High Calcium
and Magnesium Levels
Hard water contains a higher-
than-normal concentration of
calcium (Ca) and magnesium
(Mg). These minerals have
had a longer or greater
exposure to mineral-rich
rocks and soil as it flows
naturally through rivers and
waterways. It also increases
the chemical reactive levels
within the water in terms of pH,
making it much more alkaline.
Generally, whether you have hard
water or soft water is determined by
your geographical location.
What impact do these higher
concentrations of minerals have on
your plants? Generally, the presence
of more calcium and magnesium isn’t
the problem in itself — it’s the balance
between all the nutrient elements
that can and does cause problems.
The more calcium and magnesium in
the water will directly influence how
much of the other nutrients, such as
potassium and phosphorus, get locked
out and not taken up by the plant,
causing deficiencies which in turn
lead to undernourishment and growth
problems. Further to this, the positive
ions in the calcium and magnesium
will serve to increase the pH of the feed
solution and then any excess of CO 2
carbonates in the water will exacerbate
this situation further, causing the pH
to become more and more alkaline in
not only the solution but in the medium
itself. The harder the water is, the more
acid is needed to bring the pH back
down to a plant-friendly level.