FERTILIZER AND PLANT ABUSE(source:
faq:1111 "Plant Abuse Chart and Photos by Nietzsche")
Look closely, and you'll see the brown leaf edges that are
indicative of heat stress. This damage looks a lot like nutrient burn, except it
occurs only at the tops of the plants closest to the lamps. There's only one
cure for this...get the heat away from the plants, either by moving the lamps or
moving the plants.
Nutrient Solution Burn
There's a good chance that this bud was subjected to nutrient
solution burn. These symptoms are seen when the EC concentration of hydroponic
solutions is too high. These symptoms also appear when strong nutrient solution
is splashed onto the leaves under hot HID lamps, causing the leaves to burn
under the solution.
Many hydroponic gardeners see this problem. It's the
beginning of nutriet burn. It indicates that the plants have all the nutrients
they can possibly use, and there's a slight excess. Back off the concentration
of the nutrient solution just a touch, and the problem should disappear. Note
that if the plants never get any worse than this here, then the plants are
probably just fine.
Figure 4 is definitely an over-fert problem. The high level
of nutrients accumulates in the leaves and causes them to dry out and burn up as
shown here. You must flush with clear, clean water immediately to allow the
roots to recover, and prevent further damage. The find the cause of the high
The plants in Figure 1 were on a continous drip system, where
nutrient solution is constantly being pumped into the medium. This tends to keep
the entire root system completely saturated. A better way would be to
periodically feed the plants, say for 1/2 hour every 2-3 hours. This would give
the roots a chance to get needed air to them, and prevent root rot and other
Don't be throw off by the fact that the plants in Figure 2
are sitting in still water, this is actually an H2O2 solution used to try and
correct the problem. Adding an airstone to the tub would also help add O2 to the
Both of these leaves in figure 3 and figure 4 are from the
same plant. It could be over fertilization, but more likely it is due to the pH
being off. Too high or too low a pH can lock up nutrients in the form of
undisolvable salts and compounds, some of which are actually toxic to the
plants. What then happens is the grower then tries to supplement the plants diet
by adding more fertilizers, throwing off the pH even more and locking up even
more nutrients. This type of problem is seen more often in soil mixes, where
inconsistent mixing of the medium's components leads to "hot" spots.
Ozone damage typically found near the generator. Although a
rare problem, symptoms generally appear as a Mg deficiency, but the symptoms are
localized to immediately around the generator.
Root stunting is characteristic of calcium deficiency,
acidity, aluminum toxicity, and copper toxicity. Some species may also show it
when boron deficient. The shortened roots become thickened, the laterals become
stubby, peg-like, and the whole system often discolours, brown or grey.
Symptoms localized at shoot growing points.
New shoots unopened; young leaves distorted; dead leaf tips;
pale green plant copper deficiency
New shoots withered or dead; petiole or stem collapse; shoots
stunted; green plant calcium deficiency
Young leaves pale green or yellow; rosetting or dead tip;
dieback; dark green plant boron deficiency
Mobile elements are more likely to exhibit visual
deficiencies in the older leaves, because during demand these elements will be
exported to the new growth.
Nitrate - Ammonium is found in both
inorganic and organic forms in the plant, and combines with carbon, hydrogen,
oxygen and sometimes sulfur to form amino acids, amino enzymes, nucleic acids,
chlorophyll, alkaloids, and purine bases. Nitrogen rates high as molecular
weight proteins in plant tissue.
Plants need lots of N during vegging, but it's easy to overdo
it. Added too much? Flush the soil with plain water. Soluble nitrogen
(especially nitrate) is the form that's the most quickly available to the roots,
while insoluble N (like urea) first needs to be broken down by microbes in the
soil before the roots can absorb it. Avoid excessive ammonium nitrogen, which
can interfere with other nutrients.
Too much N delays flowering. Plants should be allowed to
become N-deficient late in flowering for best flavor.
Plants will exhibit lack of vigor, slow growth and will be
weak and stunted. Quality and yield will be significantly reduced. Older leaves
become yellow (chlorotic) from lack of chlorophyll. Deficient plants will
exhibit uniform light green to yellow on older leaves, these leaves may die and
drop. Leaf margins will not curled up noticeably. Chlorosis will eventually
spread throughout the plant. Stems, petioles and lower leaf surfaces may turn
As seen in figure 10 consumption of nitrogen (N) from the fan
leaves during the final phase of flowing is 100% normal.
Leaves are often dark green and in the early stages abundant
with foliage. If excess is severe, leaves will dry and begin to fall off. Root
system will remain under developed or deteriorate after time. Fruit and flower
set will be inhibited or deformed.
With breakdown of vascular tissue restricting water uptake.
Stress resistance is drastically diminished.
Phosphorus is a component of certain enzymes
and proteins, adenosine triphosphate (ATP), ribonucleic acids (RNA),
deoxyribonucleic acids (DNA) and phytin. ATP is involved in various energy
transfer reactions, and RNA and DNA are components of genetic information.
Phosphorus (P) deficiency
Figure 11 is severe phosphorus (P) deficiency during
flowering. Fan leaves are dark green or red/purple, and may turn yellow. Leaves
may curl under, go brown and die. Small-formed buds are another main symptom.
Phosphorus deficiencies exhibit slow growing, weak and
stunted plants with dark green or purple pigmentation in older leaves and stems.
Some deficiency during flowering is normal, but too much
shouldn't be tolerated. Red petioles and stems are a normal, genetic
characteristic for many varieties, plus it can also be a co-symptom of N, K, and
Mg-deficiencies, so red stems are not a foolproof sign of P-deficiency. Too much
P can lead to iron deficiency.
Purpling: accumulation of anthocyanin pigments; causes
an overall dark green color with a purple, red, or blue tint, and is the common
sign of phosphate deficiency. Some plant species and varieties respond to
phosphate deficiency by yellowing instead of purpling. Purpling is natural to
some healthy ornamentals.
Figure 12 shows Phosphorus (P) deficiency during vegatative
growth. Many people mistaken this for a fungus, but look for the damage to occur
near the end of leave, and leaves the color dull greyish with a very brittle
Phosphorus (P) Toxicity
This condition is rare and usually buffered by pH
limitations. Excess phosphorus can interfere with the availability and stability
of copper and zinc.
Potassium is involved in maintaining the
water status of the plant and the tugor pressure of it's cells and the opening
and closing of the stomata. Potassium is required in the accumulation and
translocation of carbohydrates. Lack of potassium will reduce yield and quality.
Potassium deficiency (K).
Older leaves are initially chlorotic but soon develop dark
necrotic lesions (dead tissue). First apparent on the tips and margins of the
leaves. Stem and branches may become weak and easily broken, the plant may also
stretch. The plant will become susceptible to disease and toxicity. In addition
to appearing to look like iron deficiency, the tips of the leaves curl and the
edges burn and die.
Potassium - Too much sodium (Na) displaces K, causing a K
deficiency. Sources of high salinity are: baking soda (sodium bicarbonate
"pH-up"), too much manure, and the use of water-softening filters
(which should not be used). If the problem is Na, flush the soil. K can get
locked up from too much Ca or ammonium nitrogen, and possibly cold weather.
Potassium (K) Toxicity
Usually not absorbed excessively by plants. Excess potassium
can aggravate the uptake of magnesium, manganese, zinc and iron and effect the
availability of calcium.
Magnesium is a component of the
chlorophyll molecule and serves as a cofactor in most enzymes.
Magnesium (Mg) deficiency.
Magnesium deficiency will exhibit a yellowing (which may turn
brown) and interveinal chlorosis beginning in the older leaves. The older leaves
will be the first to develop interveinal chlorosis. Starting at leaf margin or
tip and progressing inward between the veins. Notice how the veins remain
somewhat green though as can be seen in figure 15.
Notice how in Figure 16 and 17 the leaves curl upwards like
they're praying? They're praying for Mg! The tips may also twist.
This can be quickly resolved by watering with 1 tablespoon
Epsom salts/gallon of water. Until you can correct nutrient lockout, try foliar
feeding. That way the plants get all the nitrogen and Mg they need. The plants
can be foliar feed at ½ teaspoon/quart of Epsom salts (first powdered and
dissolved in some hot water). When mixing up soil, use 2 teaspoon dolomite lime
per gallon of soil.
If the starting water is above 200 ppm, that is pretty hard
water, that will lock out mg with all of the calcium in the water. Either add a
1/4 teaspoon per gallon of epsom salts or lime (both will effectively reduce the
lockout or invest into a reverse osmosis water filter.
Mg can get locked-up by too much Ca, Cl or ammonium nitrogen.
Don't overdo Mg or you'll lock up other nutrients.
Magnesium (Mg) Toxicity
Magnesium toxicity is rare and not generally exhibited
visibly. Extreme high levels will antagonize other ions in the nutrient
Zinc plays a roll in the same enzyme
functions as manganese and magnesium. More than eighty enzymes contain tightly
bound zinc essential for their function. Zinc participates in chlorophyll
formation and helps prevent chlorophyll destruction. Carbonic anhydrate has been
found to be specifically activated by zinc.
Deficiencies appear as chlorosis in the inter-veinal areas of
new leaves producing a banding appearance as seen in figure 18. This may be
accompany reduction of leaf size and a shortening between internodes. Leaf
margins are often distorted or wrinkled. Branch terminals of fruit will die back
in severe cases.
Also gets locked out due to high pH. Zn, Fe, and Mn
deficiencies often occur together, and are usually from a high pH. Don't overdo
the micro-nutrients- lower the pH if that's the problem so the nutrients become
available. Foliar feed if the plant looks real bad. Use chelated zinc. Zinc
deficiency produces "little leaf" in many species, especially woody
ones; the younger leaves are distinctly smaller than normal. Zinc defeciency may
also produce "rosetting"; the stem fails to elongate behind the
growing tip, so that the terminal leaves become tightly bunched.
Excess Zinc is extremely toxic and will cause rapid death.
Excess zinc interferes with iron causing chlorosis from iron deficiency. Excess
will cause sensitive plants to become chlorotic.
Immobile elements will show their first symptoms on younger
leaves and progress to the whole plant.
Sulfate is involved in protein
synthesis and is part of the amino acids, cystine and thiamine, which are the
building blocks of proteins. It is active in the structure and metabolism in the
plant. It is essential for respiration and the synthesis and breakdown of fatty
Sulphur (S) deficiency
The initial symptoms are the yellowing of the entire leaf
including veins usually starting with the younger leaves. Leaf tips may yellow
and curl downward. Sulfur deficiencies are light green fruit or younger leaves
with a lack of succulence. Elongated roots and woody stem. Although it's hard to
see in figure 19, the upper stems of this plant are purple. Although many
varieties of cannabis do get purplish stems, the trait generally extends the
entire length of the plant's stem, and not just near the top as in this
Leaf size will be reduced and overall growth will be stunted.
Leaves yellowing or scorched at edges. Excess may cause early senescence.
Calcium plays an important role in
maintaining cell integrity and membrane permeability.
Young leaves are affected first and become small and
distorted or chlorotic with irregular margins, spotting or necrotic areas. Bud
development is inhibited, blossom end rot and internal decay may also occur and
root may be under developed or die back. Deficiency will cause root tip
die-back, leaf tip curl and marginal necrosis and chlorosis primarily in younger
leaves. Symptoms: young leaves develop chlorosis and distortion such as
crinkling, dwarfing, developing a strap-like shape, shoots stop growing and
Difficult to distinguish visually. May precipitate with
sulfur in solution and cause clouding or residue in tank. Excess calcium may
produce deficiencies in magnesium and potassium.
Iron is an important component of plant
enzyme systems for electron transport to carry electrons during photosynthesis
and terminal respiration. It is a catalyst for chlorophyll production and is
required for nitrate and sulfate reduction and assimilation.
Iron (Fe) deficiency
Pronounced interveinal chlorosis similar to that caused by
magnesium deficiency but on the younger leaves.
Leaves exhibit chlorosis (yellowing) of the leaves mainly
between the veins, starting with the lower and middle leaves.
Caused by factors that interfere with iron absorption of
roots: over irrigation, excessive soluble salts, inadequate drainage, pests,
high substrate pH, or nematodes. This is easily corrected by adding an iron
supplement with the next watering.
Fe is unavailable to plants when the pH of the water or soil
is too high. If deficient, lower the pH to about 6.5 (for rockwool, about 5.7),
and check that you're not adding too much P, which can lock up Fe. Use iron
that's chelated for maximum availability. Read your fertilizer's ingredients -
chelated iron might read something like "iron EDTA". To much Fe
without adding enough P can cause a P-deficiency.
Note that when adding iron to the solution, it is often
necessary to not use fertilizer for that watering. Iron has a tendency of
reacting with many of the components of fertilizer solutions, and will cause
nutrient lockup to occur. Read the labels of both the iron supplement and the
fertilizer you are using before you attempt to combine the two.
Excess accumulation is rare but could cause bronzing or tiny
brown spots on leaf surface.
Manganese is involved in the oxidation
reduction process in the photosynthetic electron transport system. Biochemical
research shows that this element plays a structural role in the chloroplast
membrane system, and also activates numerous enzymes.
Interveinal chlorosis of younger leaves, necrotic lesions and
leaf shredding are typical symptom of this deficiency. High levels can cause
uneven distribution of chlorophyll resulting in blotchy appearance. Restricted
growth and failure to mature normally can also result.
Mn gets locked out when the pH is too high, and when there's
too much iron. Use chelated Mn.
Toxicity:Chlorosis, or blotchy leaf tissue due to
insufficient chlorophyll synthesis. Growth rate will slow and vigor will
Chloride is involved in the evolution
of oxygen in the photosynthesis process and is essential for cell division in
roots and leaves. Chlorine raises the cell osmotic pressure and affects stomata
regulation and increases the hydration of plant tissue. Levels less than 140 ppm
are safe for most plants. Chloride sensitive plants may experience tip or
marginal leaf burn at concentrations above 20 ppm.
Wilted chlorotic leaves become bronze in color. Roots become
stunted and thickened near tips. Plants with chlorine deficiencies will be pale
and suffer wilting.
Burning of leaf tip or margins. Bronzing, yellowing and leaf
splitting. Reduced leaf size and lower growth rate.
Boron biochemical functions are yet
uncertain, but evidence suggests it is involved in the synthesis of one of the
bases for nucleic acid (RNA uracil) formation. It may also be involved in some
cellular activities such as division, differentiation, maturation and
respiration. It is associated with pollen germination.
Plants deficient in boron exhibit brittle abnormal growth at
shoot tips and one of the earliest symptoms is failure of root tips to elongate
normally. Stem and root apical meristems often die. Root tips often become
swollen and discolored. Internal tissues may rot and become host to fungal
disease. Leaves show various symptoms which include drying, thickening,
distorting, wilting, and chlorotic or necrotic spotting.
Yellowing of leaf tip followed by necrosis of the leaves
beginning at tips or margins and progressing inward before leaves die and
prematurely fall off. Some plants are especially sensitive to boron
Copper is a constituent of many enzymes
and proteins. Assists in carbohydrate metabolism, nitrogen fixation and in the
process of oxygen reduction.
Symptoms of deficiency are a reduced or stunted growth with a
distortion of the younger leaves and growth tip die-back. Young leaves often
become dark green and twisted. They may die back or just exhibit necrotic spots.
Growth and yield will be deficient as well.
Copper is required in very small amounts and readily becomes
toxic in solution culture if not carefully controlled. Excess values will induce
iron deficiency. Root growth will be suppressed followed by symptoms of iron
chlorosis, stunting, reduced branching, abnormal darkening and thickening of
Molybdenum is a component of two major
enzyme systems involved in the nitrate reeducates, this is the process of
conversion of nitrate to ammonium.
Often interveinal chlorosis which occurs first on older
leaves, then progressing to the entire plant. Developing severely twisted
younger leaves which eventually die. Molybdenum deficiencies frequently resemble
nitrogen, with older leaves chlorotic with rolled margins and stunted growth.
Excess may cause discoloration of leaves depending on plant
species. This condition is rare but could occur from accumulation by continuous
application. Used by the plant in very small quantities. Excess mostly usually
does not effect the plant, however the consumption of high levels by grazing
animals can pose problems so she might not be too good to smoke.
Sodium seems to encourage crop yields and in specific cases
it acts as an antidoting agent against various toxic salts. It may act as a
partial substitute for potassium deficiencies. Excess may cause plant toxicity
or induce deficiencies of other elements. If sodium predominates in the solution
calcium and magnesium may be affected.
Silicon usually exists in solution as
silicic acid and is absorbed in this form. It accumulates as hydrated amorphous
silica most abundantly in walls of epidermal cells, but also in primary and
secondary walls of other cells. It is largely available in soils and is found in
water as well. Inadequate amounts of silicon can reduce tomato yields as much as
50%, cause new leaves to be deformed and inhibit fruit set. At this time
toxicity symptoms are undetermined.
Cobalt is essential to many beneficial bacteria that are
involved in nitrogen fixation of legumes. It is a component of vitamin B12 which
is essential to most animals and possibly in plants. Reports suggest that it may
be involved with enzymes needed to form aromatic compounds. Otherwise, it is not
understood fully as to its benefit to plant growth, but it is considered
essential to some animal health issues.
CANNABIS GROW GUIDE