THE MYTH SURROUNDING THE PH
The pH is a measure of the acidity or the alkalinity of the solution.
Normally the pH ranges from 0 to 14. A low pH (lower than 7)
means that a solution is acidic. Pure water has a pH of around
7 which is neutral. Higher than 7 is called alkaline. Acidic
solutions can be neutralised with alkaline solutions and vice
versa. Too acidic is fatal for any plant and so is too alkaline.
One of the causes is that the nutrients change into a, for
the plant, unabsorbable form when the pH becomes too high or low.
The pH of the nutrient solution should be checked regularly with
a pH meter.
pH too high: lower it with
- Nitric acid (during the growth period)
- Phosphoric acid (during the flowering period)
pH too low: increase it with
Take care with these acids because they are corrosive. The pH
of a nutrient solution for growing your "favourite plant"
should be between 5 and 7. Because rockwool is made from rock
and rocks can be very alkaline, rockwool can also be very alkaline
itself. This results in an immediate rise of the pH value of
the nutrient solution as soon as it comes in contact with the
rockwool. To minimize this effect, the rockwool slabs should
be soaked in nutrient solution in which the pH has been adjusted
to 5.3, at least 24 hours before using them (one slab will need
ca.10 litres). After 24 hours, measure the pH in the slab again
and adjust if necessary. The EC of this solution should be 1.7
ms. The soaking is an art. You must learn how heavy and/or moist
the slab should be. When the slab is too wet the young plant
will experience difficulties. The rockwool slab has then absorbed
so much water that there is hardly any room left for oxygen.
This results in a plant that dies from root rot.
- an alkaline solution (during the whole period)
This shows how important the use of Toprock grow blocks are.
These rockwool grow blocks are structured vertically (Toprock
slabs have a horizontal structure) which greatly improves drainage
and stimulates a rapid, healthy root development. Take all of
these factors into account because the first stage determines
the later quality level and growth strength of the plant. We
can only give guidelines in this because the pH of the tap water
differs from town to town, and might even be different from the
morning to the evening. Also the factor with which the pH in
the slab changes might differ from place to place. During the
growth period we use a pH of between 5.7 and 6.3 in the slab.
N.B: All accurate measurements need to be carried out in the slab.
To provide for an average measurement of all the slabs, use the
It is advisable to buy a hypodermic syringe to suck the liquid
out of the slab. (ca.50ml is enough for a sample, but make sure
you pour it back where it came from). If for example the pH in
the slab is 6.3 and you want it to be 6.8, then (6.3+0.5=6.8)
you need to increase the pH in the reservoir with 0.5. So if
for example the pH in the reservoir
is 5.4 you would have to make it 5.9. Between 7 and 14 days after
the flowering period is initiated (the moment you change from
18 to 12 hours of light) you gradually reduce the pH in the slab
to 6.0 which enables the plant to absorb more phosphorus. At this
time you also change from CANNA Vega to CANNA Flores.
THE MYTH SURROUNDING THE EC
The EC is for many people just as the pH values - a twilight zone,
although it is not that complicated. EC stands for Electro Conductivity
and is measured in ms; conductivity of electricity in a liquid
occurs through conductive particles. The nutrients (elements)
that are necessary for your "favourite plants" become
negatively and positively charged particles as soon as they dissolve.
The more of these particles present, the better electricity is
conducted, the higher the EC. Therefore the EC is a measure of
the amount of nutrient present in a solution. CANNA nutrients
are vital to the plant and because these nutrients are directly
available, you must proceed very carefully.
A too high EC will produce a too high osmotic pressure around
the roots. Osmosis? A liquid moves, according to physics, in
the direction of the strongest solution. Is the solution outside
the plant stronger than inside, then the plant empties itself
(simply said). This emptying of the plant can be noticed in practice
as a so called burning of the leaves. (When leaf blades curl
down they are trying to conserve water).
In general we advise that the EC with TOPROCK rockwool lies between
1.6ms and 2.5ms. (Of course we talk about the EC in the slab).
When making a nutrient solution always adjust the EC first and
only then the pH value. This is because CANNA nutrients are very
acidic and the addition of nutrient has a direct influence on
CANNA nutrients are sold in concentrated form and consist of different
parts. These parts, A and B, are packaged in separate jerrycans.
This is because the separate parts work negatively together in
their concentrated forms. Therefore always ensure that when making
a nutrient solution these concentrated part (A and B) never come
in contact with each other. Mix part A with the water and only
then add part B. If the packaging advises 1:250, then for example
begin with a solution of 1:275, then after stirring thoroughly
measure the EC and if necessary add some more to reach the correct
value. Let the nutrient solution stand for approximately 2 hours
(to work in) and then adjust the pH value.
Questions like how much feeding solution does my plant require
in week 3 and how much in week 6 are impossible to answer. This
is related to the size of the plant, the amount of leaves, height
of the lamps, relative humidity, temperature, root development,
ventilation per m/hour. The only good answer to this question
is that you must learn to see how your plant feels and learn to
feel the weight of the slab (to determine if it is wet enough).
The EC you must use also depends on the requirements of the sort.
When your plant looks healthy, fresh and green you are doing the