A
balanced spectrum of the essential nutrients
(as specified in
Chart 3.1)
can be incorporated into either a 1-part, 2-part or 3-part package.
2 & 3-part nutrients:
Most 2 & 3-part brands provide adequate levels of macro-nutrients and
trace elements. The 2 or 3 part packaging format is often deemed necessary
by manufacturers to avoid stability/ compatibility problems between
certain nutrient species when present in the same bottle (Fig 3.1).
As such, the nutrients are strategically distributed among each part. Most
importantly, the calcium is kept separate from the sulfate i.e. in a
2-part, calcium is normally in part ‘A’, whereas sulfate is in part ‘B’.
1-part
nutrient: A 1-part is able to provide superior levels of
macro-nutrients than 2 & 3-part nutrients, when it is created in the form
of a liquid “slurry”
(Graph 3.1).
The “slurry” is a fully soluble ‘suspension’ of mainly calcium sulfate
(CaSO4) within
a solution containing the balance of necessary
macro-nutrients and trace elements (Fig 3.2). The use of a slurry enables
the manufacturer to exploit the solubility limits of calcium and sulfate
to squeeze more nutrient species into a given volume than what is possible
with 2 & 3-parts.
Growers must be aware that 1-parts not based
on slurry technology are typically deficient in sulfate (S). This is
because manufacturers reduce the amount of sulfate to avoid the formation
of the crystalline precipitate which would otherwise form (Fig 3.1). An
alternative strategy used to supply ‘some’ sulfate, is to reduce the
overall nutrient concentration - particularly the calcium.
Trace elements:
Note that trace elements are often not listed on labelling due to
regulations imposed by certain jurisdictions.
Which is best: 1, 2 or 3-part nutrients?
I
n
addition to the fact that 'slurry' type 1-parts can provide a superior
nutrient balance than 2 or 3-part nutrients, if ease-of-use is desirable
then a well balanced 1-part should definitely be used.
The performance of nutrients will be reduced
when specific dosing guidelines
are not followed. Growers must take particular note when using
multi-part nutrients (e.g. 2-parts and 3-parts) as these are more complex.
For example, the separate parts should never be combined in too little
water. Further, it is important to add the correct amount of each part
(Fig 3.5).
The nutrient’s
pH
buffering capacity is an additional function that manufacturers can incorporate to
ensure on-going ease of use.
