Transcript Advanced Greenhouse Fertilization

Calcium: Cell elongation, root growth,
strengthens xylem.
Magnesium: Sits at the center of the
chloroplast molecule. Essential to
photosynthesis.
Potassium: Regulates the plants
hydration, cell wall thickness,
translocation of carbohydrates.
Ammonium Nitrogen: Building
block of proteins and amino acids.
Sodium: Damages ion exchange site
on root limiting future nutrient uptake.
Antagonizes calcium and magnesium
uptake.
Sulfur: Protein Synthesis, RNA
And DNA replication.
Phosphate: Energy creation,
regulates enzyme activity.
Nitrate Nitrogen: Building
block of proteins and amino acids.
Chloride: Detrimental ion
creating a barrier reducing water
transfer to the roots. At very high
levels it will have phytotoxic effect
when water overhead.
Boron
Builds Disease Resistance.
Copper
Function In Processes Of Photosynthesis, And Reproduction.
Iron
Catalyst For The Creation Of Chlorophyll.
Manganese
Essential In Certain Enzyme Systems.
Critical In The Role Of Nutrient Uptake During Low Light
Conditions.
Molybdenum
Required To Form The Enzyme “Nitrate Reductase” Which
Converts Nitrate Nitrogen Into Energy Within The Plant.
Zinc
Builds Enzymes And Hormones Within The Plant.

Media pH

Transpiration

Soluble Salts (Osmotic Pressure)

Root Health

Nutrient Ratio’s (antagonizing & companion)
 Water alkalinity
 Fertilizer (acidic or basic)
 Humidity
 Temperature
 Diseased
 Damaged
In Growing Media It Has
Influence On Nutrient
Availability To The Plant.
Alkaline Media Limit
Micronutrient Uptake.
Acidic Media Limits The Ions
Of Calcium, Magnesium,
And Potassium.
Neutral Media allows all
nutrients to be available.
Defined As A Decimal Logarithm Of Hydrogen Ion
Concentrations
Alkaline: Is A Low Concentration Of Hydrogen Ions
Acidic: Is A High Concentration Of Hydrogen Ions
pH: “Potential Hydrogen”
Assumption: Media
can only hold 10 free
Hydrogen Ions.
In this scenario there
are only 4 Hydrogen
Ions. (Alkaline)
pH: “Potential Hydrogen”
Assumption: Media
can only hold 10 free
Hydrogen Ions.
In this scenario there
are 8 Hydrogen Ions.
(Acidic)

Calcium Carbonate Equivalents help us
to numerically gauge the effects of
different inputs on the media pH.
› Alkalinity is the calcium carbonate
expression for bicarbonates.
› Potential acidity and basidity are the
calcium carbonate expression for impact on
media pH.

Irrigation Water
› pH Of Water Plays A Small Role In
Relevance To Media pH (Nutrient
Availability).
› Alkalinity/Bicarbonate Is The Biggest
Factor That Determines The Waters Impact
On Media Ph.

Fertilizer Selection
› Nutrient composition of Fertilizer influences
Media pH.
Defined As A Measurement Of The Ability Of A Solution To
Neutralize Acids. It Is The Sum Of Both Carbonates And
Bicarbonates.
Expressed in ppm as CaCO3 Equivalent
High Alkalinity Has A Basic Reaction On Media Ph.
Low Alkalinity Has No Neutralization On Acids Causing Media pH
Values To Decrease.
Alkalinity reacts to form Bicarbonates which
then form Hydroxide ions. Hydroxide ions
(OH-) are a strong Base.
CaCO3 (s) ↔ Ca2+ + CO32CO32- + H2O ↔ HCO3- +OH-
Alkalinity / Bicarbonate
Effect on Media pH
Alkalinity /
Bicarbonate binds the
free Hydrogen Ions in
the media. Thus
increasing our
“potential” to hold
more free Hydrogen
Ions.
Measurement to quantify a fertilizers
acidic or basic effect on substrate values
as expressed in Calcium Carbonate
Equivalents.
The pounds of Calcium Carbonate estimated to be
required to neutralize the acidity caused by adding 1
ton of acid forming fertilizer to the growing media.
Primarily based on Ammoniacal nitrogens effect on the
growing media from the process of nitrification.
2 NH4+ + 3 O2 → 2 NO2- + 2 H2O + 4 H+ (Nitrosomonas)
2 NO2- + O2 → 2 NO3- (Nitrobacter, Nitrospina)
Sulfates contribute to number.
This reaction is independent of the plant. It occurs as soon as
the fertilizer touches the media.
The pounds of Calcium Carbonate estimated
to be equal to the addition of 1 ton of a base
forming fertilizer to the soil.
The basicifying effect caused by a base
fertilizer requires the plant to interact with the
fertilizer. When cations like Calcium,
Magnesium, or potassium are brought up into
the plant they bring Hydrogen with them. Thus,
increasing the potential for more hydrogen in
the soil.

Transpiration

Root Health

Relative tissue concentrations

Osmotic Pressure

Nutrient Ratios
Nutrient Mobility in
the Plant
KK C
N
NM
M
N
N C ga
M
M
g
gg
C
a
a
Measurement of the amount of nutrients, salts or
impurities in water.
High electrical conductivity can create an
osmotic pressure that will reduce water and
nutrient uptake. Potentially causing damage the
roots of the plant.
Nutrient properties of water are
expressed as either Cation’s, or
Anion’s.
Cation’s are molecule’s with a
positive charge on their
valence. Hydrogen, Calcium,
Magnesium, Potassium,
Sodium, and Ammonium.
Anion’s are molecule’s with a
negative charge on their
valence. Sulfur, phosphate,
nitrate, carbonate,
bicarbonate, and chloride.
Cation’s (positively charged) couple
with Anions (negatively charged) to
enter into the plant.
Ions compete (antagonize) with
similar ions for uptake.
Some nutrients have a different
number of charges on their valence.
This makes some more efficient than
others in entering the plant.
Cation’s
Ca++
Mg++
K+
NH4+
Na+
Anion’s
NO3CLSO4- PO4

Begin With a water test.
› Know nutrients already being provide for.
› Know water effects on substrate pH.
› Waters contribution to salt load.

What crops are being grown
› What nutrient levels are required?
› What’s the optimal media pH?
› Optimal fertility rates (salt sensitive)

Low Alkalinity (0-50 ppm)- Use basic fertilizer (13-213, 15-0-15, 16-3-16) Calcium and Magnesium
deficient in water. Must be supplied from fertilizer.

Moderate Alkalinity (50-140 ppm)- Use Neutral To
Slightly Acidic Formulas (17-5-17, 16-3-16, 17-17-17)
Some Ca & Mg May Be Needed

High Alkalinity (140-250 ppm)-Use Acidic Formulas
(20-10-20 or 18-6-18) -Ca & Mg Usually Present In
Water
› Ideally acidification is used to improve fertilizer selection.

May not supply the nutrients the plant needs.
› Acid forming fertilizers are limited in their calcium,
magnesium content.

Varying feed rates have varying impact on
substrate pH.
› Could lead to high salts in substrate.
› Potential nightmare with heavy feeders having too
low of pH, and light feeders having too high a pH.

Acid forming fertilizers (ammonium based)
cause a vegetative response.
› Increased use of plant growth regulators.

Acid Injection

Target Alkalinity

Leave Some Alkalinity- Target 80120 ppm-

Phosphoric- Can Stretch- Lower P
In Fertilizer

Sulfuric Used Most- 35% (Safest) Or
93% (Most Economical)

Citric -Expensive & Limited
Neutralization

Injector Must Be Acid Compatible

Know crops nutritive needs.

Know Nutrient levels provided by water.

Match Nutrients in fertilizer to
complement those in water.

Match fertilizer acidity/basidity to water
alkalinity.
Woburn, MA
May 4, 2016
Water Analysis
Sample No: 112059-1
Sample Description: Water
SECTION 1: MAJOR CATIONS
Calcium
Magnesium
Sodium
Potassium
MAJOR ANIONS
Sulphate
Phosphate
Chloride
Carbonate ALK
Bicarbonate ALK
SECTION 2:
NO3-N [ppm]
pH
EC [mmho/cm]
NH4-N [ppm]
Total Alk [ppm]
F [ppm]
SECTION 3: TRACE ELEMENTS
Aluminum (Al)
Boron
Copper (Cu)
Iron (Fe)
Manganese (Mn)
Molybdenum (Mo)
Zinc (Zn)
ppm
5.18
0.96
34.69
1.82
ppm
3.98
0.39
46.00
5.76
52.90
0.60
8.91
0.21
0.10
47.20
ppm
0.06
0.02
0.02
0.03
0.01
0.01
ND
meq
0.26
0.08
1.51
0.05
meq
0.08
0.01
1.28
0.19
0.87

Concerns:
› Calcium and magnesium are non existent.
› Sodium proportionally high in ratio to
calcium and magnesium.
› Alkalinity is moderately low. Acid forming
fertilizers should be avoided.

Strategies:
› General crops: use 16-3-16 or 17-5-17.
› Potted Plants (poinsettias) rotate every third
feeding with 15-0-15.
May 1, 2013
Water Analysis
Sample No: 100806-4
Sample Description: Water
SECTION 1: MAJOR CATIONS
Calcium (Ca)
Magnesium
Sodium
Potassium
MAJOR ANIONS
Sulphate (SO4-S)
Phosphate
Chloride (Cl)
Carbonates
Bicarbonates
SECTION 2:
NO3-N [ppm]
pH
EC [mmho/cm]
NH4-N [ppm]
Total Alk [ppm]
F [ppm]
SECTION 3: TRACE ELEMENTS
Aluminum (Al)
Boron
Copper (Cu)
Iron (Fe)
Manganese (Mn)
Molybdenum (Mo)
Zinc (Zn)
ppm
39.72
12.18
15.04
2.49
ppm
20.05
0.47
34.00
0
131.06
ND
6.86
0.39
ND
107.43
ppm
0.07
0.04
0.01
0.01
ND
0.03
0.01
meq
1.99
1.02
0.65
0.06
meq
0.42
0.02
0.94
0
2.15

Concerns:
› Calcium is low, magnesium is non existent.
› Alkalinity is moderate at 107 ppm. (80 ideal).

Strategies:
› General crops use16-3-13, or 17-5-17
› Low pH preferring plants: rotate every other
feeding with 18-6-18.
Benefits
Determines nutritional Status of plants
Diagnosis suspected fertility problems
Prevents problems from developing
Alerts us to potential nutrient problems
caused by applying too much fertilizer
or too much water.
Allows for quickly correcting a nutrient
issue.





Test is done using 1 part soil to 2 parts
distilled water.
Sample should be taken from the bottom
2/3 of pot.
Soil to be collected at same compaction
level as found in pot.
Soil and distilled water should sit before
taking test. Allows time for the distilled water
to take on characteristics of soil.
Ideally samples are taken from multiple
pots.
1:2 dilution Method
Expressed as millimhos (mmhos)
0 - 0.25
Interpretation
Very Low
Probable deficiency
0.25 - 0.75
Seedlings and salt sensitive plants
0.75 - 1.25
Desirable for most Plants
1.25 - 1.75
Slightly High
Ideal for poinsettias during growth
stage.
1.75 - 2.25
Reduced growth, leaf margin burn,
and possible root damage.

Low pH
› Micronutrients of iron, manganese, zinc, and
boron are highly soluble. Therefore these
nutrients are readily taken up by the plant
and possibly causing a toxicity.

High pH
› Micronutrients of iron, manganese, zinc, and
boron are less soluble. This potentially causes
a micronutrient deficiency,
Iron inefficient plants
pH 5.4-6.2
General Group
pH 5.8-6.4
Iron Efficient Plants
pH 6.0-6.6
Bacopa
Chrysanthemum
Geranium (seed &
Zonal)
Calibrochoa
Ivy Geranium
Marigold
Nemesia
Impatients
New Guniea
Impatients
Pansy/Viola
Poinsettia
Lisianthus
Petunia
Snapdragon
Scaevola




Injectors lose calibration
over time.
Many nutrient
deficiencies are from
injector not delivering
assumed rates.
Injectors used for
chemigation require
accuracy.
Hose End
Nutrient Solution

Subtract fertilizer and water
ec from water.
› Example: 2.02-0.31=1.71

Find ec for fertilizer being
injected on chart at 100
ppm.
› Example:16-3-16@100
ppm = 0.68

Divide ec of fertilizer
solution by fertilizers stated
100 ppm Nitrogen Value.
› Example: 1.71/0.68=2.51

This tells us that we are
delivering 250 ppm
Nitrogen at hose end.
Media pH determined by water alkalinity.
Electrical conductivity impacts plant growth.
Nutrient ratios influence one another’s uptake.
Sodium has detrimental impact on plant health.
Select fertilizer that complements waters nutritional needs.
Know your fertilizers impact on media pH.