WaltersGardensTotalGrowLightTesting

TestSummary:

Thepotentialfora2/3powerconsumptionreductionbyreplacing1000Whighpressuresodiumlightswith150WTotalGrowTG15AlightswastestedandprovenbycomparinggrowthcharacteristicsofseveralWaltersGardensperennials.Eightcharacteristicsweremeasuredon11varietiesofplantsin2growthstagesusing3lightintensitiesrepresentinglesser,equivalentandgreaterthancurrentWaltersGardenslightinglevels.

Plantstested:

MonardaLeadingLadyPlum(showandproduction,3lightintensities) EchinaceaJulia(show,3intensities) Heucherella(show,3intensities) AgaveQWT(production,3intensities) CarexBananaBoat(production,3intensities) CoreopsisMoonbeam(production,3intensities) CoreopsisZagreb(production,3intensitieslostfrominadequatewatering) DianthusFireStar(production,3intensities) GeraniumRozanne(production,mediumintensity) EchinaceaKimsKneeHigh(production,mediumintensity) HakonechloaAureola(production,mediumintensity)

GrowthDataCollected:

Height(all10varieties) Diameter(6varieties) Largestleaflength&width(7varieties) Branching(Monarda) Totalshoots(6varieties) LeafCount(6varieties) RootScore(all10varieties)

ResultsSummary:

TheTotalGrowlightingstrategytestedrequiresonlyonethirdofthepowerconsumptionofthe1000WHPSlightingsystemwhileconsistentlyyieldingstatisticallyequalgrowth.Mostvariationinthedataisbetterattributedtouncontrolledvariablesthantothelighting,especiallydifferingsoilmoisturelevelsduetovaryingamountsofairflowandoccasionallyinconsistentwatering.Whencombiningdatafromallvarieties,alltraitswerewithinonestandarddeviationofdifferencebetweenlightingtypeswithonlyheightandbranchingdifferingbymorethan0.5standarddeviations(greaterinTGduetogreaterMonardashowplantsizes).Averagelightintensitiesweretargetedat25%higherunderHPStotesttheabilityoftheTotalGrowspectrumtobeequallyeffectiveatalowerlightintensity.Averagelight

intensities,measuredinmole*m2*s1PAR,were21%higherunderHPSareasthanTotalGrowareaswhenmeasuredwithanOceanOpticsUSB2000spectrometerandamobileintegratingsphere.Rootgrowthandqualityappearedtobethecharacteristicmoststronglycorrelatedwithlightintensity,showingimprovementathigherintensitiesregardlessoflightingtype.

Resultsindetail:

Evaluatingeachdatacategorybynumberoftrialswithgreatervaluesfromeachlightingtypeandaveragemagnitudeofvariation,measuredbystandarddeviations(SDs):

HeightTGgreaterin16/29trials(.6SDs)o GreatestforTGinMonardaandHeucherellashowplantsandAgaveandGeranium

productionplants,greatestforHPSinCoreopsisMoonbeamandDianthus DiameterTGgreaterin9/19trials(.1SDs)

o GreatestforTGinMonarda,EchinaceaandHeucherellashowplants,greatestforHPSinDianthus

LargestleaflengthandwidthTGgreaterin10/18trials(.2SDs)o GreatestforTGinMonardaandHeucherellashowplants,allothersverysimilar

MainBranches(Monardashowplantsonly)TGgreaterin2/3trials(.9SDs) TotalShootsHPSgreaterin13/20trials(.3SDs)

o GreatestforHPSinMonardaproductionplantsandCarex LeafCountHPSgreaterin12/17trials(.1SDs)

o GreatestforTGinMonardashowplants,greatestforHPSinMonardaproductionplantsandEchinaceaKimsKneeHigh

RootScoreHPSgreaterin16/29trials(.3SDs)o GreatestforHPSinCarex,CoreopsisMoonbeamandEchinaceaKimsKneeHigh,all

othersverysimilar

Foreachcharacteristic,therewasanear5050splitoftrialswithgreaterresultsbetweenthetwolightingtypes.Combinedwiththesmallmagnitudeoftheaveragevariationsbetweentreatments,theseresultsstronglysuggestthatthelightingusedwasaninsignificantsourceofvariation.

Focusingonlightingintensity,itwasexpectedthatthemediumlightintensitywouldproducethemedianvalueforeachgrowthcategories.Inreality,mediumlightlevelsactuallyproducedthesmallestaveragenumbersforhalfofthedatacategoriesinbothlightingtypes.Thisisbestexplainedbythegreaterimpactoftheothervariablesinfluencinggrowth.Thismediumlightinglevelisthemostrelevant,however,asitrepresentstheamountoflightcurrentlyprovidedinthegreenhouses.Also,flatstestedundermediumlightlevelsweremostsimilarlypositionedrelativetofansandthusshouldhavesimilarlevelsofmoisture.Everyplantalsohadatleastonemediumlightingtreatmentflatwhile3productionplantsdidnothaveloworhighintensityflats.Height,diameter,largestleaflength&width,leafcount,andMonardasbranchingallweregreateronaverageunderTGlighting(0.5,0.9,0.5,3.0and2.0SDsofaveragedifference,respectively)whiletotalshootsandrootscorewereaslightlygreaterunderHPS(0.3and0.3SDsofaveragedifference,respectively).

Rootdatawasalsoselectivelyanalyzed.Rootscoresweredeterminedbytakingpicturesofeachplantsrootsandgivingascorebetween05relativetotheotherplants.Thiswasthusthemostsubjectiveofthedatacategoriestaken.Especiallydryorwetsoilwasnotedaswellasseverityofboltinginfloweringplants.Bothlightingtreatmentsproducedthebestresultsunderhighlightingwithmediumlightslightlyoutperforminglowlight.Boltinghadinconsistenteffects.WetanddryconditionsappearedtoadverselyaffectrootdevelopmentaswellexceptfordryandnormalconditionshavingequalresultsforHPS.Overall,HPShadaslightadvantageinaveragerootsscores.Byobservation,itappearedthatTGplantsoccasionallyhadlarger,whiterrootsthanHPSwhileHPSplantshadagreaternumberofsmaller,brownercoloredroots.

Discussion:

Plantsgrownunder1000WHPSandtheeffectiveequivalentamountof150WTG15Alightsdidnotdemonstrateanyconsistentsignificantdifference.Occasionalvariationswithinthesmallsamplesizesofindividualplantvarietiesandlightintensitieswerebetterattributedtouncontrolledvariablesthantolightsourceastheyfavoredeachlightsourcerelativelyequally.Forexample,MonardaandHeucherellashowplantsunderTotalGrowlightsrelativelyconsistentlyoutscoredHPStrials,butDianthusandCarexplantsunderHPSlightsshowedsimilartrendsovertheirTGequivalents.

Whencombiningallresults,thereappearstobeaslighttrendofTGplantshavinggreaterabovegroundgrowthandHPSplantshavinggreatergrowthinrootsandnewshoots.ThismaybeduetotheradiantheatofHPSlightsthatdriesoutsoilmorequickly.TheresultsshouldbedriersoilsunderHPSplantsthanTGplantswhichwouldfavorrootdevelopmentoverabovegrounddevelopment.GrowingunderTGlightsmightallowreducedwateringneedstomaintaindriersoilsandbetterrootgrowthwhendesired.

Rootgrowthalsoappearedtobethecharacteristicmostdirectlyimprovedbyincreasedlightingintensities,especiallyunderTGlighting.Averagerootscoresimprovedby0.6(ona05scale)forbothlightingtypeswiththeincreasefromlowtohighlightingintensity.Itwastheonlycategorythatincreasedbothfromlowtomediumintensityandmediumtohighintensityunderbothlightingtypes.Again,thismaybeconfoundedbyincreasingsoiltemperaturesanddrynessunderincreasedlights,butrepresentsanopportunitytorefinegrowingstrategiestoimproverootgrowthwhenthatisapriority.

Figures:

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Figure1TotalGrowPARoutput(mole*m2*s1).Squaresrepresentonesquarefoot.RedareasrepresentlowerthannormallevelsofequivalentsupplementallightingforWaltersGardensgreenhouses,greenrepresentsnormalrangesandyellowrepresentsincreasedlevels.Blueboxesshowactualareasusedfortestingtheselightlevels.DarkgreenareasareidealtestareasduetocomparableairflowlevelstodarkgreenareasunderHPSlighting(seefigure2).Thickoutlinesrepresentfixturelocations.

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96 91 88 88 91 96 ## ## ## ## 92 85 80 76 75 74 74 75 76 80 85 92 ## ## ## ## 96 91 88 88 91 96 Figure2HighPressureSodiumoutput(mole*m2*s1).Squaresrepresentonesquarefoot.RedareasrepresentlowerthannormallevelsofequivalentsupplementallightingforWaltersGardensgreenhouses,greenrepresentsnormalrangesandyellowrepresentsincreasedlevels.Blueboxesshowactualareasusedfortestingtheselightlevels.DarkgreenareasareidealtestareasduetocomparableairflowlevelstodarkgreenareasunderTGlighting(seefigure1).Thickoutlinesrepresentfixturelocations.

0.000.200.400.600.801.001.201.40

Averages(AllPlants)

TotalGrow

HPS

Figure3Normalizedaveragesforthe8measuredcategoriesofgrowthforallplantsundereachlightingtreatment.Errorbarsrepresentonestandarddeviationgreaterorless.

0.000.200.400.600.801.001.201.401.60

LightIntensityAverages(AllPlants)

TGLow

TGMed

TGHigh

HPSLow

HPSMed

HPSHigh

Figure4Normalizedaveragesforeachgrowthcategoryseparatedbybothlightingtypeandlightintensity.Errorbarsrepresentonestandarddeviationgreaterorless.

Figure5TotalGrowtestareaattheendofthetest.

Figure6TotalGrowfinishingplantstestsatweek1andweek8.

Figure7TotalGrowproductionplantstestatweek1andweek8.Moreplantvarietieswereaddedasthetestprogressed.