Advanced Greenhouse Fertilization By Joe Slater Plant Marvel Labs

Cations 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.

Anions 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.

Micronutrient’s Boron Copper Iron Manganese Molybdenum Zinc 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.

Liebig's Law of the Minimum: Plant growth will excel to the limit imposed by the nutrient in least relative supply.

Factors Influencing Nutrient Uptake and Availability Media pH Water alkalinity Fertilizer (acidic or basic) Transpiration Humidity Temperature Soluble Salts (Osmotic Pressure) Root Health Diseased Damaged Nutrient Ratio’s (antagonizing & companion)

Why is pH Important in Plant Growth? 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.

Soil-less pH Nutrient Availability Graph

What is pH? 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 CaCO3 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.

Inputs that cause Media pH values to change 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.

Alkalinity 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.

How High water Alkalinity Increases Substrate pH Alkalinity reacts to form Bicarbonates which then form Hydroxide ions. Hydroxide ions (OH-) are a strong Base. CaCO3 (s) ↔ Ca2+ + CO32- CO32- + 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.

Fertilizer Selection Influences Media pH

Potential Acidity & Basicity Measurement to quantify a fertilizers acidic or basic effect on substrate values as expressed in Calcium Carbonate Equivalents.

Potential Acidity 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.

Potential Basicity 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.

Factors Influencing Nutrient Utilization. Transpiration Root Health Relative tissue concentrations Osmotic Pressure Nutrient Ratios

Transpiration Effects Nutrient Uptake.

Nutrient Mobility in the Plant K K K K N N N N Ca Ca Ca Ca N N N N Mg Mg Mg Mg Mg Mg Mg Ca Ca Ca Ca Ca Ca Ca Ca

Electrical Conductivity (EC) 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.

Relationships Between Nutrients

Nutrients in the Water 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.

Nutrient Interactions 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 Anion’s Ca++ NO3- Mg++ CL- K+ SO4- - NH4+ PO4 Na+

Periodic Table of the Elements

Part 2 Putting It all Together!

What's Needed to design a Program 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)

Matching Alkalinity & Fertilizer Low Alkalinity (0-50 ppm)- Use basic fertilizer (13-2-13, 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.

Disadvantages to Using Fertilizer to Control Substrate pH. 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.

Controlling Substrate pH with High Water Alkalinity. Acid Injection Target Alkalinity Leave Some Alkalinity- Target 80-120 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

Designing Our Fertility Program 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.

Water Analysis Woburn, MA May 4, 2016 Sample No: 112059 - 1 Sample Description: Water SECTION 1: MAJOR CATIONS ppm meq Calcium 5.18 0.26 Magnesium 0.96 0.08 Sodium 34.69 1.51 Potassium 1.82 0.05 MAJOR ANIONS Sulphate 3.98 Phosphate 0.39 0.01 Chloride 46.00 1.28 Carbonate ALK 5.76 0.19 Bicarbonate ALK 52.90 0.87 SECTION 2: NO3 N [ppm] 0. 60 pH 8. 91 EC [mmho/cm] 0.2 NH4 10 Total Alk [ppm] 47.20 F [ppm] SECTION 3: TRACE ELEMENTS Aluminum (Al) 0.0 6 Boron 2 Copper (Cu) Iron (Fe) 3 Manganese (Mn) Molybdenum (Mo) Zinc (Zn) ND

Strategies for This Water 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.

Strategies for This Water 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.

Crop Management In house Testing of Electrical Conductivity and pH. 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.

1:2 Soil Test Method 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.

Calibrate Meter

Take Sample From Bottom 2/3 of Media

1 Part Media to 2 parts Distilled Water.

Mix and Let Sit

Take EC and pH Readings

Interpreting Soluble Salt (EC) Values 1:2 dilution Method Expressed as millimhos (mmhos) Interpretation 0 - 0.25 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.

Understanding pH Low pH High 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 Crop Specific pH Guide 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

Checking Fertility Rate at Hose End Injectors lose calibration over time. Many nutrient deficiencies are from injector not delivering assumed rates. Injectors used for chemigation require accuracy.

Determine Conductivity of Clear Water

Determine Conductivity of Fertilizer Solution Hose End Nutrient Solution

Determine Fertility Rate 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.

Summary 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.