Maximum Yield Cannabis USA April/May 2018 | Page 23

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EVEN IF your medium has a proper
amount or even an abundance of
nutrients, they may be locked out if
the pH is not correct for your crops.”
Nutrient availability is not the only reason to seek ideal pH
levels for your cannabis. Retention of nutrients is also affected
by pH. Plant nutrients may leach out more readily when pH
levels are below 5.0 and above 7.5. Some elements that are
required for good growth can become toxic to your plants at
inappropriate pH levels. Aluminum, for instance, can become
toxic at levels below 5.0. Beneficial bacteria are also affected
by your media’s pH. Bacteria are most efficient at releasing
nutrients like nitrogen from organic matter if your soil has a
pH between 5.5 and 7.0.
The ideal pH range for cannabis crops differs depending on
the growing media, but is generally between about 5.8 and 6.5.
Each strain will have its preference. If you are growing can-
nabis hydroponically, keep the pH between the high fives and
low sixes, and if you are growing in any other substrate, aim
to keep the pH in the low-to-mid-six range.
Electrical Conductivity
Potential of Hydrogen
Different growers may debate what is the single most impor-
tant factor in getting the most out of your crops, but if the pH
is not within an acceptable range, your nutrient levels and
even your EC readings will be useless. Potential of hydrogen
is a measure of the concentration of hydrogen (H) ions. The
“p” in pH comes from the German word for power, potenz. A
pH meter will measure the power of the hydrogen ions.
The pH scale ranges from 0.0 to 14.0 (for practical purposes,
this is true; there are readings outside of this range).
Readings of less than 7.0 register as being acid, or “sour;”
readings above 7.0 are alkaline (base), or “sweet.” A neutral
pH is 7.0. There are several reasons it is important to find and
maintain a proper pH for your cannabis crops (or any other
crop). Not all nutrients are in an available form for your plant
to use at all points on the pH scale. Some are more available
in the acidic range, while some are more available in the
alkaline. This means even if your medium has a proper
amount or even an abundance of nutrients, they may be
locked out if the pH is not correct for your crops.
myhydrolife.com
Electrical conductivity is one method of measuring the amount
of fertilizer or nutrients present in your crop’s medium, thus
giving you an idea if your cannabis crop is undernourished
or overfed. The EC is a measure of the total dissolved solids
(TDS) in your water. The readings will usually be in parts per
million (ppm) or in milligrams per liter (mg/l). Either scale will
give the same reading. Besides having an accurate EC meter,
it is imperative to know what the EC of your water is before
even starting to grow. Ideally, the EC of your irrigation water
or reservoir before adding nutrients will be zero. A reverse os-
mosis system will give you an EC of zero if you live in an area
where your water has some level of EC.
The EC value you want to see when testing your cannabis
medium will vary depending on the phase of growth it is in.
Like pH, the nutrient needs will also vary depending on if your
crops are grown hydroponically or in other media and can also
vary depending on the strain being grown.
For young seedlings, a typical EC range should be between
about 0.8 and 1.3; for clones, this range can dip to 0.5-1.3. In
hydroponic grows, it may be on the lower end of the range. It
may be higher in other media. During the vegetative phase,
it should be higher and be somewhere around 1.3-1.7. This
value should continue to climb leading up to and including
the flowering phase, where the EC should hover up around
two. If your EC ranges are not at or near these, it’s time to take
action. If your readings are too low, slowly add more nutrients
until you are at an ideal range. If your readings are too high,
back off the nutrients and flush out and replace your reservoir
or leach out the nutrients in your medium until proper levels
have been restored.
grow. heal. learn. enjoy.
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