Contributed by: Mr. HIGHway
Images archived: 2002
These photographs were taken from Cannabis World
through an exhaustive search of the Archives. I would
like the take the time to thank every member at Cannabis
World for their contributions who made this all
possible. I hope it helps as many people as possible.
I will start with the mobile elements, or the
?Main nutrients? of Nitrogen, Potassium, and
Phosphorous. Next will be Magnesium, Sulphur, Calcium,
and Iron. Next is what we call the ?Trace Elements? of
Molybdenum, Copper, Zinc, Boron, and Manganese. These
are the 12 elements that Cannabis needs to survive, in
order of importance.
The ?Trace Elements? are
only needed in very small quantities; if they are
present in large quantities, they can lockout other
elements - which mask as other problems! Some will even
fool you by masking as Over fertilization, or another
Nitrogen is a key
Element in the production of Amino Acids, which are the
building block of Proteins. Many plant hormones contain
Nitrogen as well as Chlorophyll, DNA and RNA (Genetic
materials), and a myriad of enzymes that help control
and regulate growth. Nitrogen is the most mobile
Plants suffering from this deficiency
are distinct in their pattern of yellowing. Yellowing
starts on the older leaves and progresses upward,
leaving the top parts of the plant green.
that the large fan leaves are yellowing and turning
purple-ish. from the bottom up.
Feeding with a
high N fert will clear it up, like an emulsion of fish
[Editor?s note: Leaves will turn pale
green, then yellow evenly. There are no intervenial
striping or yellow patches. Color is uniform over the
entire leaf. Yellowing is expected during flushing, as
the plant is using up all available internal nutrients]
used for plant energy by being assimilated into
molecules called Adenosine-tri-phosphate, or ATP. This
molecule is necessary for any plant activity that
requires energy such as root growth, flowering,
respiration, and vegetative growth.
Phosphorous deficiencies are distinct.
Purple stems, leaf stems, leaf veins and stunted growth
are a sure sign of a Phosphorous deficiency. Leaves will
also tend to be smaller and dark green, and may or may
not include necrotic patches. Bud size will be smaller
and underdeveloped, as will the root mass.
good all-around fertilizer like Peter's 20-20-20 will
clear this up.
Potassium serves to aid in the process of
photosynthesis, nutrient uptake, respiration, and is a
key to sturdy stems and disease resistance. Having an
adequate supply for the plant early in it?s life stage
will keep your seedlings from falling over.
Potassium deficiencies are identified by
necrosis on the margins of larger fan leaves. Necrotic
patches can be seen on the leaves as well. Leaves will
eventually turn yellow, brown and die off. Most of the
plants that show signs of a Potassium deficiency are
going to be the tallest and best looking plants you
Again, feeding with a good all-around
fertilizer will clear it up as well.
also use wood ashes and water them into your soil to fix
this. You'll need to replace your soil's holding
capacity of Potassium, and have a surplus before it will
become available to the roots again. Minor Nutrients
seeing anything but an Iron deficiency are slim, but
when pushing the envelope with HID?s and CO2 enrichment,
they will pop up from time to time. Most are seen, if
ever, in outdoor grows.
Chlorophyll has the
same structure as Hemoglobin, except that it has a
magnesium atom in place of the Iron atom. Chlorophyll is
how plants make sugars to feed the process of building
ATP through the Krebs cycle.
magnesium deficient plant is identified by intervenial
chlorosis, necrosis, and eventually a lockout of plant
nutrients. The problems starts at the bottom of the
plants and works it?s way up.
These images depict different stages and
signs of a magnesium deficiency. The first picture is a
Mg deficient plant in flower, and the second two are of
the leaves to show what I mean by Intervenial Chlorosis.
Treating with an Epsom salts mix will clear this
Sulphur is an important
element in the structures of amino acids and proteins,
and is needed for normal plant respiration and
metabolism of sugars and other compounds.
ever see this in your plants, then you can be assured
that you have this deficiency. Look for yellowing
starting from the top, and progressing down, including
the veins of the leaves. Treat the same as a Mg
Calcium is an important
co-enzyme in the production of fatty acids, cell
membranes, and is necessary for normal mitosis/cell
division. A Ca deficiency will stunt plant growth.
Acidic soils may increase the risk of a Ca def.
The six trace elements of
Boron, Copper, Iron, Manganese, Molybdenum, and Zinc are
not required in large quantities, but are important in
the transfer of energy in plant processes.
This is a rare occurrence
and is exemplified by small gray or necrotic patches on
the growing shoots which eventually die.
this is done easily by applying a foliar spray of
eyewash containing Boric Acid. This picture is not
really the best IMO, but it shows a gray patch on a leaf
that is indicative of what to look for. This will most
likely occur in outdoor grows.
A copper deficiency is
commonly mistaken for an over fertilization problem, but
it is set apart by the growing tips dieing off first
along with the crispy leaves. The new shoots will die
from the tips and margins first, often going brown or
even white before they die.
A foliar feeding
with a commercial fungicide containing Copper (ie.
Copper Sulphate) will clear it up, but the damaged
leaves may never recover.
An Iron deficiency will
mask a Magnesium deficiency. If you look at the newer
growth, that will be where the plant exhibits the
intervenial chlorosis typically differentiating it from
a Magnesium deficiency.
Notice how the top of the plant is
exhibiting intervenial chlorosis and the lower part is
A Manganese deficiency
exhibits a general chlorosis, followed by yellowing
patches and necrotic patches between the veins of the
larger fan leaves.
Molybdenum deficient plant will exhibit yellowing
necrotic leaves from the tips inward, with necrotic
lesions present from the tips inward. A very distinctive
feature is that it occurs in the middle of the plant. It
also may spread to the rest of the plant if not stopped,
eventually killing your plant.
Elements may be added to your soil mix as you prepare it
for planting. A good Hydroponic nutrient should contain
ample micros to get your plant through its lifecycle.
A Zinc deficient plant is
obvious from the wispy new growth with twisted leaflets
at 90. There is also intervenial chlorosis at the top
of the plant that is commonly confused with an Iron
Notice in this picture that the
older grown leaves are relatively unaffected and healthy
Other persistent problems
Improper pH can cause an
abundance of problems that you might easily confuse with
other problems or deficiencies.
A pH imbalance
may also be the cause of the deficiencies in the first
place. pH in soil is best in the range of 6 up to 7.5,
and in a Hydroponic system it?s best at 5.2-5.8.
The following chart exemplifies this.
This is a
very common problem that can be disguised as an improper
pH, or light burning, as well as a myriad of other
The first picture masks as over
Nitrification, but notice how the entire leaf is curled
under, not just the tip.
This photo displays many problems
associated with overferting, some of which could be a
simple imbalance of pH and a certain nutrient/micro
lockout at the given pH.
lack of Dissolved Oxygen
Droopy leaves and lower leaf yellowing are
indications of persistent over watering problems.
pictures show the ?claw?: indicative of over
Nitrification. Some growers loadup their plants with
Nitrogen prior to flowering. This will prepare them for
the stretch to follow, and will increase bud production
if induced a few weeks prior to blooming the plant.
Radiant heat is also called ?light burn?. Typically,
topmost leaves will become pale green, then turn brown
as the burn progresses. Plants on the outmost edge of
the garden will remain a healthy dark green, with light
burned plants directly underneath the reflectors in a