Water Quality And Greenhouse Crops Bodie Pennisi University of Georgia.

Water QualityWater QualityAnd And

Greenhouse CropsGreenhouse Crops

Bodie PennisiBodie PennisiUniversity of GeorgiaUniversity of Georgia

Why Need To Know Water Why Need To Know Water Quality ?Quality ?

Irrigation water affects pH of the Irrigation water affects pH of the soil solution soil solution

pH controls nutrient mobilitypH controls nutrient mobility

Water quality is Water quality is NOTNOT static! static!

Media pH is affected by:Media pH is affected by:

lime incorporated lime incorporated

water alkalinity and pHwater alkalinity and pH

type of fertilizer used type of fertilizer used (basic or acidic)(basic or acidic)

Factors that Affect Medium pHFactors that Affect Medium pHFactors that Affect Medium pHFactors that Affect Medium pH

Buffering capacity of the mediumBuffering capacity of the medium.. peat, bark, coir, perlite, vermiculitepeat, bark, coir, perlite, vermiculite

indirectly - how much lime is incorporated? indirectly - how much lime is incorporated?

directly – type and rate of limedirectly – type and rate of lime

type of limestone: calcitic (CaCOtype of limestone: calcitic (CaCO33, more reactive) or , more reactive) or dolomitic (CaMgCOdolomitic (CaMgCO33))

particle size: the finer the more reactiveparticle size: the finer the more reactive

hardness: agricultural limestone is soft and reactive, hardness: agricultural limestone is soft and reactive, building limestone is non-reactivebuilding limestone is non-reactive

The Goal Is To The Goal Is To Achieve A Achieve A

Stable Medium Stable Medium pH Over TimepH Over Time

The Goal Is To The Goal Is To Achieve A Achieve A

Stable Medium Stable Medium pH Over TimepH Over Time

Alkalinity TermsAlkalinity TermsAlkalinity TermsAlkalinity Terms

Milliequivalents Milliequivalents alkalinity alkalinity

mg/liter or mg/liter or ppm CaCOppm CaCO33 of alkalinity of alkalinity

11

22

33

44

55

mg/liter or mg/liter or ppm ppm

bicarbonate bicarbonate

5050

100100

150150

200200

250250

6060

122122

183183

244244

305305

Sample ASample A Sample BSample B

pH = 9pH = 9 pH = 7pH = 7

One drop of acid to get pH 6One drop of acid to get pH 6 Ten drops of acid to get pH 6Ten drops of acid to get pH 6

The Effect of Water Alkalinity on Media The Effect of Water Alkalinity on Media pH and Acid RequirementpH and Acid Requirement

The Effect of Water Alkalinity on Media The Effect of Water Alkalinity on Media pH and Acid RequirementpH and Acid Requirement

Little or no effect on the Little or no effect on the growing medium pHgrowing medium pH

Increases growing medium Increases growing medium pHpH

Alk = 50 Alk = 50 ppmppm Alk = 300 Alk = 300 ppmppm

pH affects the solubility of fertilizers, pH affects the solubility of fertilizers, and the efficacy of pesticides and and the efficacy of pesticides and growth regulators.growth regulators.

the higher the water pH the less the higher the water pH the less soluble these materials aresoluble these materials are

pH pH pH pH

CaMg(COCaMg(CO33))22

Dolomitic Dolomitic

limestonelimestone

CaCa2+2+ + Mg + Mg2+2+ + 2CO + 2CO332-2-

HardnessHardness

AlkalinityAlkalinity

Hardness and Alkalinity Generally Hardness and Alkalinity Generally Go Hand-In-Hand but They Are Go Hand-In-Hand but They Are

NOT One and the SameNOT One and the Same

You Can Use the Water Hardness You Can Use the Water Hardness to Estimate Its Alkalinityto Estimate Its Alkalinity

Calcium and magnesium are the major Calcium and magnesium are the major contributorscontributors

“ “hard water” has a high Ca and/or Mghard water” has a high Ca and/or Mg “ “hard water” is hard water” is generallygenerally associated associated with high alkalinitywith high alkalinity can have hard water and low can have hard water and low alkalinity – water high in CaClalkalinity – water high in CaCl2 2 and/orand/or

MgClMgCl22

HardnessHardnessHardnessHardness

If you have hard water:If you have hard water: check Ca and Mg concentrationscheck Ca and Mg concentrations

if high use less limeif high use less lime monitor pH !monitor pH !

check Ca : Mg ratiocheck Ca : Mg ratio ideal ratio is 3:1 if expressed in meq/Lideal ratio is 3:1 if expressed in meq/L ideal ratio is 5:1 if expressed in ppmideal ratio is 5:1 if expressed in ppm

HardnessHardnessHardnessHardness

HH22COCO332CO2CO332- 2- + 2H + 2H ++

HH22O + COO + CO22

Substrate Substrate AcidityAcidity

AlkalinityAlkalinity

Both the alkalinity and Both the alkalinity and the acidity are neutralizedthe acidity are neutralized

What is “best” alkalinity level ?What is “best” alkalinity level ? (One that maintains stable media-pH over (One that maintains stable media-pH over time)time) Research says anywhere between Research says anywhere between 40 and 120 ppm bicarbonate40 and 120 ppm bicarbonate However, there is probably However, there is probably notnot ONE best ONE best alkalinity level ! Depends on: alkalinity level ! Depends on:

the length of the crop cyclethe length of the crop cycle the plant to substrate ratiothe plant to substrate ratio upper substrate pH that the crop can upper substrate pH that the crop can toleratetolerate

AlkalinityAlkalinityAlkalinityAlkalinity

6.0

6.5

7.0

7.5

0% 15% 35% 55%

Poinsettia Crop 10 Weeks After PlantingPoinsettia Crop 10 Weeks After Planting(adopted from (adopted from Greenhouse GrowerGreenhouse Grower, January 2001, p.72), January 2001, p.72)

Leaching FractionLeaching Fraction

Med

ia p

HM

edia

pH

The more water applied to the crop, the greater The more water applied to the crop, the greater effect high alkalinity water will have on media pH.effect high alkalinity water will have on media pH.

Initial media pH = 6.0Initial media pH = 6.0Water alkalinity = 320 ppm CaCOWater alkalinity = 320 ppm CaCO33

Alkalinity GuidelinesAlkalinity GuidelinesPot Diameter/Size Impacts the Effect Pot Diameter/Size Impacts the Effect

of Alkalinity of Alkalinity ((From Scotts Testing Lab)From Scotts Testing Lab)

Alkalinity GuidelinesAlkalinity GuidelinesPot Diameter/Size Impacts the Effect Pot Diameter/Size Impacts the Effect

of Alkalinity of Alkalinity ((From Scotts Testing Lab)From Scotts Testing Lab)

Container SizeContainer Size Optimum Optimum Range ppm Range ppm

CaCOCaCO33

Level of Level of Concern*Concern*

PlugsPlugsSmall pots/ Small pots/ shallow flatsshallow flats4”-5” pots/deep flats4”-5” pots/deep flats6” or larger 6” or larger pots/long term pots/long term cropscrops

* The highest level that a grower can manage depends on the plant species, media * The highest level that a grower can manage depends on the plant species, media type, potential acidity of feed program and watering practices.type, potential acidity of feed program and watering practices.* The highest level that a grower can manage depends on the plant species, media * The highest level that a grower can manage depends on the plant species, media type, potential acidity of feed program and watering practices.type, potential acidity of feed program and watering practices.

60 - 10060 - 100

80 - 12080 - 120

100 - 140100 - 140

120 - 180120 - 180

< 40, > 120< 40, > 120

< 40, > 140< 40, > 140

< 40, > 160< 40, > 160

< 60, > 200< 60, > 200

Fertilizers Fertilizers and and

WaterWater

Fertilizers Fertilizers and and

WaterWater

the fertilizer solution you apply to the crop is the fertilizer solution you apply to the crop is made up of irrigation water and water-soluble made up of irrigation water and water-soluble fertilizer;fertilizer;

it is the combination of the alkalinity in the it is the combination of the alkalinity in the irrigation water and the reaction of the water-irrigation water and the reaction of the water-soluble fertilizer that affects media pH;soluble fertilizer that affects media pH;

the balance between the ammonical nitrogen the balance between the ammonical nitrogen in the fertilizer and water alkalinity has the in the fertilizer and water alkalinity has the greatest effect on media pH over time.greatest effect on media pH over time.

It Is Important To Remember:It Is Important To Remember:

5

6

7

8

9

0 4 8 12 16

Well (320 ppmalkalinity)

Acidified well (120ppm alkalinity)

Well +RO Blend (130ppm alkalinity)

RO purified (<20 ppmalkalinity)

Weeks from PlantingWeeks from Planting

Roo

t M

edia

pH

Roo

t M

edia

pH

The same fertilizer 97% The same fertilizer 97% nitrate nitrogen at 200 nitrate nitrogen at 200

ppm N was appliedppm N was applied

(adopted from (adopted from Greenhouse GrowerGreenhouse Grower, , January 2001, p.72)January 2001, p.72)

Effect of Water Alkalinity on Media pH Effect of Water Alkalinity on Media pH Over TimeOver Time

5

6

7

8

9

0 2 4 8 12 16

50% NH4-N/50%NO3-N+320 ppmalkalinity25% NH4-N/75%NO3-N+120 ppmalkalinity25% NH4-N/75%NO3-N+130 ppmalkalinity3% NH4-N/97%NO3-N+20 ppmalkalinity


Roo

t M

edia

pH

Roo

t M

edia

pH

(adopted from (adopted from Greenhouse GrowerGreenhouse Grower, , February 2001, p.68)February 2001, p.68)

Stable Media pH Can Be Obtained By Number Stable Media pH Can Be Obtained By Number of Different Ways by Manipulating Both the of Different Ways by Manipulating Both the NHNH44-N to NO-N to NO33 N Ratio and Water Alkalinity N Ratio and Water Alkalinity

3

4

5

6

7

8

0 4 8 12 16

Media #1Media #2Media #3


Roo

t M

edia

pH

Roo

t M

edia

pH

(adopted from (adopted from Greenhouse GrowerGreenhouse Grower, , February 2001, p.72)February 2001, p.72)

Residual Lime’s EffectsResidual Lime’s Effects

Media #1 contained Media #1 contained hydrated lime (leaves hydrated lime (leaves no residual lime in the no residual lime in the media)media)Media #2 contained Media #2 contained same peat as #1 but a same peat as #1 but a dolomite was used dolomite was used (large residual)(large residual)Media #3 contained Media #3 contained the same rate of the same rate of dolomite as #2 but dolomite as #2 but used a different peat used a different peat with higher lime with higher lime requirementrequirement

The same acidic fertilizer (50% The same acidic fertilizer (50% ammonical N at 200 ppm with water ammonical N at 200 ppm with water

alkalinity of 200 ppm CaCOalkalinity of 200 ppm CaCO33) was used) was used

Approximate Guidelines to Matching Fertilizers with Water Approximate Guidelines to Matching Fertilizers with Water Alkalinity in Order to Achieve a Stable pH Over Time. Use these Alkalinity in Order to Achieve a Stable pH Over Time. Use these

values as a starting point only. It is up to the grower to make values as a starting point only. It is up to the grower to make changes in media pH that are based on actual pH measurements in changes in media pH that are based on actual pH measurements in

the crop.the crop. (adopted from (adopted from Greenhouse GrowerGreenhouse Grower, February 2001, p.62, February 2001, p.62))

Approximate Guidelines to Matching Fertilizers with Water Approximate Guidelines to Matching Fertilizers with Water Alkalinity in Order to Achieve a Stable pH Over Time. Use these Alkalinity in Order to Achieve a Stable pH Over Time. Use these

values as a starting point only. It is up to the grower to make values as a starting point only. It is up to the grower to make changes in media pH that are based on actual pH measurements in changes in media pH that are based on actual pH measurements in

the crop.the crop. (adopted from (adopted from Greenhouse GrowerGreenhouse Grower, February 2001, p.62, February 2001, p.62))

CaCOCaCO3 3

Equivalency Equivalency (lbs/ton)(lbs/ton)

% Acidic % Acidic Nitrogen = Nitrogen =

(ammonium + (ammonium + urea)/ total Nurea)/ total N

> 500 acidic> 500 acidic > 50%> 50%

150-500 acidic150-500 acidic

150 acidic to 150 acidic to 150 basic150 basic

> 150 basic> 150 basic

20-30%20-30%

40%40%

<15%<15%

ExamplesExamples

20-20-2020-20-2025-10-1025-10-1020-10-2020-10-2021-5-2021-5-20

20-0-2020-0-2017-5-1717-5-1713-2-1313-2-1314-0-1414-0-14

Alkalinity Alkalinity concentration concentration

(ppm CaCO(ppm CaCO33) that ) that provides a stable provides a stable

media pHmedia pH

200-300200-300

150-250150-250

60-12060-120

30-6030-60

Dealing With Dealing With High And Low High And Low

Water Water AlkalinityAlkalinity

Dealing With Dealing With High And Low High And Low

Water Water AlkalinityAlkalinity

Action Steps To Correct High AlkalinityAction Steps To Correct High AlkalinityAction Steps To Correct High AlkalinityAction Steps To Correct High Alkalinity

reverse osmosis

acid injection

acid fertilizer and/or

none

less lime

Alkalinity Alkalinity (ppm) (ppm)

bicarbonatebicarbonate

480480

180180

120120

If acid injection required, use the Alkalinity If acid injection required, use the Alkalinity Calculator found on:Calculator found on:

www.ces.ncsu.edu/depts/hort/floriculture/www.ces.ncsu.edu/depts/hort/floriculture/software/software/

Correcting High AlkalinityCorrecting High AlkalinityCorrecting High AlkalinityCorrecting High Alkalinity

Most commonly used acids: sulfuric, Most commonly used acids: sulfuric, phosphoric, nitric.phosphoric, nitric.

Need to consider the extra phosphorus (P), Need to consider the extra phosphorus (P), nitrogen (N), or sulfur (S) in the acid when nitrogen (N), or sulfur (S) in the acid when selecting fertilizer.selecting fertilizer.

3.4 fl oz of 85% phosphoric acid/100 gal 3.4 fl oz of 85% phosphoric acid/100 gal adds 122 ppm P to the irrigation wateradds 122 ppm P to the irrigation water

If acid is changed, nutritional program needs If acid is changed, nutritional program needs to be re-evaluated.to be re-evaluated.


With some injectors may be difficult to figure With some injectors may be difficult to figure out how much acid is being added. The solution out how much acid is being added. The solution pH can give a pH can give a roughrough estimate of how much estimate of how much alkalinity is left:alkalinity is left:

a solution pH of 5.2 will have about 40 ppm a solution pH of 5.2 will have about 40 ppm alkalinity; pH of 5.8 - about 80 ppm; alkalinity; pH of 5.8 - about 80 ppm; pH of 6.2 – about 120 ppm. pH of 6.2 – about 120 ppm.

Needs to measure alkalinity with a test kit in-Needs to measure alkalinity with a test kit in-house or a lab test.house or a lab test.


Low alkalinity is not desirable.Low alkalinity is not desirable. the buffering capacity of the irrigation the buffering capacity of the irrigation solution is low solution is low

if using acidic fertilizers it can lead to if using acidic fertilizers it can lead to low substrate pH and increased low substrate pH and increased micronutrient levelsmicronutrient levels using nitrate fertilizers will raise the using nitrate fertilizers will raise the media pH and keep it at a constant level media pH and keep it at a constant level and not cause it increaseand not cause it increase

Low AlkalinityLow AlkalinityLow AlkalinityLow Alkalinity

If alkalinity is less than 40 ppm, you may If alkalinity is less than 40 ppm, you may consider:consider:

increasing the lime in the mediaincreasing the lime in the media

using basic (nitrate-based) fertilizerusing basic (nitrate-based) fertilizer

If pH falls below 5.8 for sensitive crops:If pH falls below 5.8 for sensitive crops:

apply flowable lime or potassium apply flowable lime or potassium bicarbonate and check pH after 3 daysbicarbonate and check pH after 3 days

re-apply again if pH remains below 6.0 after re-apply again if pH remains below 6.0 after 3 days. 3 days.

Low AlkalinityLow AlkalinityLow AlkalinityLow Alkalinity

Research showed that rates of 4 lbs/100 gal KHCOResearch showed that rates of 4 lbs/100 gal KHCO33 or or

4 qts/100 gal flowable lime can cause phytotoxicity to 4 qts/100 gal flowable lime can cause phytotoxicity to roots or foliage if solution is not immediately rinsed off roots or foliage if solution is not immediately rinsed off foliage.foliage.

recommended rates are 2 lbs/100 gal KHCOrecommended rates are 2 lbs/100 gal KHCO33 or or

4 qts/100 gal flowable lime 4 qts/100 gal flowable lime

If applying potassium bicarbonate follow the day after If applying potassium bicarbonate follow the day after with heavy leaching with basic fertilizer that contains Ca with heavy leaching with basic fertilizer that contains Ca and Mg (such as 13-2-13 or 14-0-14) to remove high levels and Mg (such as 13-2-13 or 14-0-14) to remove high levels of potassium and restore nutrient balance.of potassium and restore nutrient balance.

Tips for Using Flowable Lime or Tips for Using Flowable Lime or Potassium Bicarbonate (KHCOPotassium Bicarbonate (KHCO33))Tips for Using Flowable Lime or Tips for Using Flowable Lime or Potassium Bicarbonate (KHCOPotassium Bicarbonate (KHCO33))

Tips for Using Flowable Lime or Tips for Using Flowable Lime or Potassium Bicarbonate (KHCOPotassium Bicarbonate (KHCO33))Tips for Using Flowable Lime or Tips for Using Flowable Lime or Potassium Bicarbonate (KHCOPotassium Bicarbonate (KHCO33))

Do not apply to dry soil. Media should rewet and Do not apply to dry soil. Media should rewet and absorb the chemical easily.absorb the chemical easily.

Apply sufficient volume to achieve at least 30% Apply sufficient volume to achieve at least 30% leaching.leaching.

Apply in cool part of the day so that lime does not Apply in cool part of the day so that lime does not dry quickly on foliage and can be easily washed off.dry quickly on foliage and can be easily washed off.

Immediately rinse foliage before chemical dries Immediately rinse foliage before chemical dries using clear water in a back-pack sprayer.using clear water in a back-pack sprayer.

Other FactorsOther Factors

SalinitySalinitySalinitySalinity

Total Dissolved Salts (TDS) – all salts Total Dissolved Salts (TDS) – all salts present in the water (1 mMho/cm=640 ppm)present in the water (1 mMho/cm=640 ppm) less than 0.75 less than 0.75 mMhomMho /cm for plugs /cm for plugs less than 1.0 less than 1.0 mMhomMho /cm for other /cm for other

greenhouse cropsgreenhouse crops less than 2.0 less than 2.0 mMhomMho /cm for other nursery /cm for other nursery

cropscrops

SalinitySalinitySalinitySalinity

Sodium – high sodium can interfere with MgSodium – high sodium can interfere with Mg2+2+ and Caand Ca2+2+ availability, and cause foliar burns availability, and cause foliar burns associated with poor water uptake and sodium associated with poor water uptake and sodium accumulation in the tissues.accumulation in the tissues. Sodium Adsorption Ratio (SAR)Sodium Adsorption Ratio (SAR)

problem if higher than 4 meq/Lproblem if higher than 4 meq/L

Iron and Iron-Fixing BacteriaIron and Iron-Fixing Bacteria

Excess iron and iron bacteria can cause Excess iron and iron bacteria can cause unsightly brown stains or bluish sheen on unsightly brown stains or bluish sheen on foliage and flowers. foliage and flowers. As little as 0.3 ppm iron in the water could As little as 0.3 ppm iron in the water could

lead to deposits if overhead irrigation is used lead to deposits if overhead irrigation is used and the sheen can cause clogging in drip and the sheen can cause clogging in drip systems. systems.

Iron problems can come from two sources: Iron problems can come from two sources: well water that contains iron, and iron-fixing well water that contains iron, and iron-fixing bacteria in water storage basinsbacteria in water storage basins. .

IRON CONTROL METHODSIRON CONTROL METHODS There are several ways to control iron slime problems. There are several ways to control iron slime problems. The common denominator of all treatments is prevention of the The common denominator of all treatments is prevention of the formation of slime.formation of slime.Basically there are two preventive treatments:Basically there are two preventive treatments:

1.1. STABILIZATION (Precipitation Inhibitors)STABILIZATION (Precipitation Inhibitors)Stabilization treatments keep the ferrous iron in solution by Stabilization treatments keep the ferrous iron in solution by chelating it with sequestering agents. Such agents include chelating it with sequestering agents. Such agents include various poly phosphates and phosphonate. various poly phosphates and phosphonate.

2.2. OXIDATION - SEDIMENTATION - FILTRATION OXIDATION - SEDIMENTATION - FILTRATION This type of treatment oxidizes the soluble "invisible" ferrous This type of treatment oxidizes the soluble "invisible" ferrous iron into the insoluble "visible" ferric iron. It then will iron into the insoluble "visible" ferric iron. It then will precipitate, so it can be physically separated from the water by precipitate, so it can be physically separated from the water by filtration. filtration.

Removing Iron and Iron-Fixing BacteriaRemoving Iron and Iron-Fixing Bacteria

Aerate irrigation water in a holding pond, which Aerate irrigation water in a holding pond, which allows for the iron to precipitate before it reaches the allows for the iron to precipitate before it reaches the plants. plants.

If iron-fixing bacteria are present, this measure may If iron-fixing bacteria are present, this measure may not be sufficient. Adjust the irrigation intake location. not be sufficient. Adjust the irrigation intake location. The intake should be located 18 to 30“ below the The intake should be located 18 to 30“ below the surface to avoid pulling in the oily surface sheen, at surface to avoid pulling in the oily surface sheen, at least 18” deep to prevent "vortexing" from the least 18” deep to prevent "vortexing" from the surface, and should be up from the bottom to avoid surface, and should be up from the bottom to avoid pulling up iron sediment. pulling up iron sediment.

The next step is to install a basin aeration pump, The next step is to install a basin aeration pump, which helps precipitate the iron, thus reducing the which helps precipitate the iron, thus reducing the food source for the iron bacteria. food source for the iron bacteria.

Removing Iron and Iron-Fixing BacteriaRemoving Iron and Iron-Fixing Bacteria Inject chlorine in the water in conjunction with an Inject chlorine in the water in conjunction with an

irrigation filter. The chlorine must be in contact with irrigation filter. The chlorine must be in contact with irrigation water for one minute to be effective. To irrigation water for one minute to be effective. To accommodate the chlorine injection, the irrigation accommodate the chlorine injection, the irrigation system needs retrofitting, which may require storage system needs retrofitting, which may require storage tanks, swirl chambers or extra loops in the irrigation tanks, swirl chambers or extra loops in the irrigation lines. lines.

Two forms of chlorine can be used: gas or liquid. Two forms of chlorine can be used: gas or liquid. Gas is the most efficient and effective, but is also Gas is the most efficient and effective, but is also hazardous. Liquid chlorine injection is safer. A hazardous. Liquid chlorine injection is safer. A filtering system that removes organic residue will filtering system that removes organic residue will reduce the amount of chlorine required. Usually two reduce the amount of chlorine required. Usually two filters are installed, so one can be back flushed and filters are installed, so one can be back flushed and cleaned while the other is filtering irrigation water. cleaned while the other is filtering irrigation water.

MicronutrientsMicronutrientsMicronutrientsMicronutrients

Chlorine – commonly associated with sodium Chlorine – commonly associated with sodium (NaCl); (NaCl); problem if > than 2 meq/L.problem if > than 2 meq/L.

Fluorine – levels above 1 ppm may cause foliar Fluorine – levels above 1 ppm may cause foliar problems on sensitive crops such as lilies and problems on sensitive crops such as lilies and freesias; it can accumulate in the media.freesias; it can accumulate in the media.

Boron – high levels are associated with Boron – high levels are associated with alkaline soils in areas of low rainfall; alkaline soils in areas of low rainfall; problem if > than 0.5 ppm. problem if > than 0.5 ppm.

Managing High Salinity in Managing High Salinity in Water SupplyWater Supply

Managing High Salinity in Managing High Salinity in Water SupplyWater Supply

DiluteDilute with collected rainwater or with collected rainwater or other low salinity water sourcesother low salinity water sources

Use reverse osmosis water Use reverse osmosis water treatment, particularly for misting treatment, particularly for misting cuttings, irrigating seedlings, and cuttings, irrigating seedlings, and salt-sensitive cropssalt-sensitive crops

Where Does Where Does The Water The Water

Come From ?Come From ?

25

20

15

10

5

0

Fre

qu

ency

%

Irrigation Water Alkalinity concentrations Irrigation Water Alkalinity concentrations (ppm CaCO(ppm CaCO33) from Florida) from Florida

<40

40–8

0

80-2

0

120-

160

160-

200

200-

240

240-

280

280-

320

320-

360

360-

400

>40

0

Testing The Testing The Waters …Waters …

Testing Water Quality Testing Water Quality In-HouseIn-HouseTesting Water Quality Testing Water Quality In-HouseIn-House

Range 0-8 meq/L (0-400 ppm Range 0-8 meq/L (0-400 ppm alkalinity expressed as CaCOalkalinity expressed as CaCO33))

Accuracy Accuracy 0.4 meq/L or better 0.4 meq/L or better Kits from $30 for 100 tests toKits from $30 for 100 tests to

$155 for 100 tests. $155 for 100 tests.

Water Quality KitWater Quality KitWater Quality KitWater Quality Kit

Commercial Commercial LabLab

1.1. Need test for alkalinityNeed test for alkalinity2.2. Need Need Fluorine (F) and/or Chlorine Fluorine (F) and/or Chlorine

(Cl) if high levels are suspected.(Cl) if high levels are suspected.

How Often How Often Should Water Should Water Quality Be Quality Be

Checked?Checked?

How Often How Often Should Water Should Water Quality Be Quality Be

Checked?Checked?

Soil ZoneSoil ZoneSand and Gravel Sand and Gravel

AquiferAquifer

Limestone or Limestone or Granite AquiferGranite Aquifer

Sandstone Sandstone AquiferAquifer

Examples of Variation in Groundwater Examples of Variation in Groundwater QualityQuality

Examples of Variation in Groundwater Examples of Variation in Groundwater QualityQuality

Well # 1 Well # 2 Well # 3

Water Quality Should Be Water Quality Should Be Checked:Checked:

Water Quality Should Be Water Quality Should Be Checked:Checked:

Every time a new water Every time a new water source is added.source is added.

Once during a dry season Once during a dry season and once during rainy season.and once during rainy season.

More frequently with More frequently with shallow wells.shallow wells.

The The Plan From Plan From Now On …Now On …

The The Plan From Plan From Now On …Now On …

Pre-test irrigation water and media before Pre-test irrigation water and media before planting.planting.

Stock up on pH-adjusting chemicals and Stock up on pH-adjusting chemicals and basic fertilizers.basic fertilizers.

Use a water test analysis to select the Use a water test analysis to select the fertilizer and decide whether to acidify fertilizer and decide whether to acidify irrigation water.irrigation water.

Set up a pH, EC and nutrient monitoring Set up a pH, EC and nutrient monitoring program. program.

Water Quality And Greenhouse Crops Bodie Pennisi University of Georgia.

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Transcript of Water Quality And Greenhouse Crops Bodie Pennisi University of Georgia.