Optimal Rate of Organic Fertilizer during the Vegetative-stage for Cannabis Grown in Two Coir-based Substrates

in HortScience

Cannabis producers, especially those with organic operations, lack reliable information on the fertilization requirements for their crops. To determine the optimal organic fertilizer rate for vegetative-stage cannabis (Cannabis sativa L.), five rates that supplied 117, 234, 351, 468, and 585 mg N/L of a liquid organic fertilizer (4.0N–1.3P–1.7K) were applied to container-grown plants with one of two coir-based organic substrates. The trial was conducted in a walk-in growth chamber and the two substrates used were ABcann UNIMIX 1-HP with lower water-holding capacity (WHC) and ABcann UNIMIX 1 with higher WHC. No differences in growth or floral dry weight (yield) were found between the two substrates. Pooled data from both substrates showed that the highest yield was achieved at a rate that supplied 389 mg N/L (interpolated from yield-fertilizer responses) which was 1.8 times higher than that of the lowest fertilizer rate. The concentration of ∆9-tetrahydrocannabinol (THC) in dry floral material was maximized at a rate that supplied 418 mg N/L, and no fertilizer rate effects were observed on Δ9-tetrahydrocannabidiolic acid (THCA) or cannabinol (CBN). The highest yield, cannabinoid content, and plant growth were achieved around an organic fertilizer rate that supplied 389 mg N/L during the vegetative growth stage when using the two coir-based organic substrates.

Contributor Notes

We thank ABcann Medicinals Inc. for providing funding as well as materials, expertise, and ground-level support. We would also like to thank Millenniumsoils Coir and EZ-GRO Inc. for providing materials and technical support.

Corresponding author. E-mail: yzheng@uoguelph.ca.



  • View in gallery

    Response of cannabis growth attributes to organic fertilizer (4.0N–1.3P–1.7K) rate [indicated by nitrogen (N) concentration] applied during the vegetative stage. Values are means ± se and lines are the best fit regression relationships at P < 0.05. For days 5 and 13, n = 10; for day 19, n = 20 (vegetative stage; left); for days 45 and 63 (flowering stage; right) at rates that supplied 117, 234, and 468 mg N/L, n = 12; at rates that supplied 351 and 585 mg N/L, n = 11.

  • View in gallery

    Response of cannabis yield to organic fertilizer (4.0N–1.3P–1.7K) rate [indicated by nitrogen (N) concentration] applied during the vegetative stage. Values are means ± se. The curve is the best fit regression relationship with P < 0.05 (n = 12 at rates that supplied 117, 234, and 468 mg N/L; n = 11 for rates that supplied 351 and 585 mg N/L).

  • View in gallery

    Relationship between ∆9-tetrahydrocannabinol (THC) concentration in dry floral material of cannabis and organic fertilizer (4.0N–1.3P–1.7K) rate [indicated by nitrogen (N) concentration] applied during the vegetative stage. Values are means ± se. The curve is the best fit regression relationship with P < 0.05 (n = 3).

  • View in gallery

    Relationships between cannabinoid concentrations in dry floral material of cannabis and dry floral weight. Values are means ± se (n = 15 for THCA and THC; n = 13 for CBN). Lines are the best fit regression relationships with P < 0.05. THCA = Δ9-tetrahydrocannabidiolic acid; THC = ∆9-tetrahydrocannabinol; CBN = cannabinol.

  • View in gallery

    Response of substrate pH and electrical conductivity to organic fertilizer (4.0N–1.3P–1.7K) rate [indicated by nitrogen (N) concentration] applied during the vegetative stage. Data are means ± se (n = 5 for pH at the 585 mg N/L rate on day 17 and n = 10 for all other means) and lines are the best fit regression relationships with P < 0.05.

  • View in gallery

    Response of substrate pH during the flowering stage to organic fertilizer (4.0N–1.3P–1.7K) rate [indicated by nitrogen (N) concentration] applied during the vegetative stage. Data are means ± se (n = 8), and lines are the best fit regression relationships with P < 0.05.


AhmedS.A.RossS.A.SladeD.RadwanM.M.KhanI.A.ElSohlyM.A.2015Minor oxygenated cannabinoids from high potency Cannabis sativa LPhytochemistry117194199

AhmedS.A.RossS.A.SladeD.RadwanM.M.ZulfiqarF.ElSohlyM.A.2008Cannabinoid ester constituents from high potency Cannabis sativa LPlanta Med.74536542

AmaducciS.ScordiaD.LiuF.H.ZhangQ.GuoH.TestaG.CosentinoS.L.2015Key cultivation techniques for hemp in Europe and ChinaInd. Crops Prod.68216

ArcView Market Research and New Frontier2014The state of legal marijuana markets. 4th ed. ArcView Mkt. Res. New Frontier San Francisco CA

AubinM.-P.SeguinP.VanasseA.TremblayG.F.MustafaA.F.CharronJ.-B.2015Industrial hemp response to nitrogen, phosphorus, and potassium fertilizationCrop Forage Turfgrass Mgt.1110

BaxterW.J.ScheifeleG.2008Growing industrial hemp in Ontario. Ontario Ministry of Agriculture Food and Rural Affairs. Queen’s Printer for Ontario Toronto Canada

BowleyS.1999A hitchhiker’s guide to statistics in plant biology. Any Old Subject Books Guelph Canada

Canada Gazette2016SOR/2016-230 s.2. Access to cannabis for medical purposes regulations. P.C. 2016-743 (5 Aug. 2016). Canada Gazette Part II. 150(17) 3525. 23 Nov. 2016. <http://gazette.gc.ca/rp-pr/p2/2016/2016-08-24/html/sor-dors230-eng.php>. Archived 25 Aug. 2016

CervantesJ.2006Marijuana horticulture: The indoor/outdoor medical grower’s bible. Van Patten Publishing Vancouver WA

EhrensingD.T.1998Feasibility of industrial hemp production in the United States pacific northwest. Oregan State Univ. Agr. Expt. Sta. Bul. 681

ElSohlyM.A.SladeD.2005Chemical constituents of marijuana: The complex mixture of natural cannabinoidsLife Sci.78539548

ElzingaS.FischedickJ.PodkolinskiR.RaberJ.C.2015Cannabinoids and terpenes as chemotaxonomic markers in cannabisNat. Prod. Chem. Res.319

FaragS.KayserO.2015Cultivation and breeding of Cannabis sativa L. for preparation of standardized extracts for medicinal purposes. Medicinal and aromatic plants of the world. Springer Netherlands Dordrecht The Netherlands

GülA.KıdoğluF.AnaçD.2007Effect of nutrient sources on cucumber production in different substratesSci. Hort.113216220

HilligK.W.MahlbergP.G.2004A chemotaxonomic analysis of cannabinoid variation in cannabis (Cannabaceae)Amer. J. Bot.91966975

JohnsonC.N.FisherP.R.VetanovetzR.P.ArgoW.R.2011Quantifying the acidity and basicity of fertilizers in container substratesActa Hort.891159166

KimuraM.OkamotoK.1970Distribution of tetrahydrocannabinolic acid in fresh wild cannabisExperientia26819820

LeggettT.2006Review of the world cannabis situationBull. Narc.581155

MechoulamR.ShaniA.EderyH.GrunfeldY.1970Chemical basis of hashish activityScience169611612

MuntendamR.HappyanaN.ErkelensT.BruiningF.KayserO.2012Time dependent metabolomics and transcriptional analysis of cannabinoid biosynthesis in Cannabis sativa var. Bedrobinol and Bediol grown under standardized condition and with genetic homogeneityIntl. J. Med. Plants Res.13140

PotterD.J.2014A review of the cultivation and processing of cannabis (Cannabis sativa L.) for production of prescription medicines in the UKDrug Test. Anal.63138

PotterD.J.DuncombeP.2012The effect of electrical lighting power and irradiance on indoor-grown cannabis potency and yieldJ. Forensic Sci.57618622

PrasadM.SimmonsP.MaherM.J.2004Release characteristics of organic fertilizersActa Hort.644163170

RavivM.LiethJ.H.2007Soilless culture: Theory and practice. 1st ed. Elsevier B.V. Burlington MA

RossS.A.ElSohlyM.A.1997CBN and ∆9-THC concentration ratio as an indicator of the age of stored marijuana samplesBull. Narc.49139

RussoE.B.2007History of cannabis and its preparations in saga, science, and sobriquetChem. Biodivers.416141648

RussoE.B.2011Taming THC: Potential cannabis synergy and phytocannabinoid-terpenoid entourage effectsBrit. J. Pharmacol.16313441364

RuterJ.M.1992Influence of source, rate, and method of applicating controlled release fertilizer on nutrient release and growth of “Savannah” hollyFert. Res.32101106

ShinoharaM.AoyamaC.FujiwaraK.WatanabeA.OhmoriH.UeharaY.TakanoM.2011Microbial mineralization of organic nitrogen into nitrate to allow the use of organic fertilizer in hydroponicsSoil Sci. Plant Nutr.57190203

SilberA.Ben YonesL.DoriI.2004Rhizosphere pH as a result of nitrogen levels and NH4/NO3 ratio and its effect on zinc availability and on growth of rice flower (Ozothamnus diosmifolius)Plant Soil262205213

SonneveldC.BaasR.NijssenH.M.C.de HoogJ.1999Salt tolerance of flower crops grown in soilless cultureJ. Plant Nutr.2210331048

SurrageV.A.LafrenièreC.DixonM.ZhengY.2010Benefits of vermicompost as a constituent of growing substrates used in the production of organic greenhouse tomatoesHortScience4515101515

TanakaA.FujitaK.1974Nutrio-physiological studies on the tomato plantSoil Sci. Plant Nutr.20305315

TaschwerM.SchmidM.G.2015Determination of the relative percentage distribution of THCA and Δ(9)-THC in herbal cannabis seized in Austria - Impact of different storage temperatures on stabilityForensic Sci. Intl.254167171

United Nations Office on Drugs and Crime2009Recommended methods for the identification and analysis of cannabis and cannabis products manual for use by national drug analysis laboratories. Laboratory and Scientific Section United Nations Office on Drugs and Crime Vienna Austria

van BakelH.StoutJ.M.CoteA.G.TallonC.M.SharpeA.G.HughesT.R.PageJ.E.2011The draft genome and transcriptome of Cannabis sativaGenome Biol.12117

VanhoveW.SurmontT.Van DammeP.De RuyverB.2012Yield and turnover of illicit indoor cannabis (Cannabis spp.) plantations in BelgiumForensic Sci. Intl.220265270

VanhoveW.Van DammeP.MeertN.2011Factors determining yield and quality of illicit indoor cannabis (Cannabis spp.) productionForensic Sci. Intl.212158163

VeraC.L.MalhiS.S.RaneyJ.P.WangZ.H.2004The effect of N and P fertilization on growth, seed yield and quality of industrial hemp in the Parkland region of SaskatchewanCan. J. Plant Sci.84939947

VogelmannA.F.TurnerJ.C.MahlbergP.G.1988Cannabinoid composition in seedlings compared to adult plants of Cannabis sativaJ. Nat. Prod.5110751079

VollnerL.BieniekD.KorteF.1986Review of analytical methods for identification and quantification of cannabis productsRegul. Toxicol. Pharmacol.6348358

WangY.T.2000Impact of a high phosphorus fertilizer and timing of termination of fertilization on flowering of a hybrid moth orchidHortScience356062

WrightR.D.1986The pour-through nutrient extraction procedureHortScience21227229

WrightR.D.NiemieraA.X.1987Nutrition of container-grown woody nursery cropsHort. Rev.975101

ZhaiZ.EhretD.L.ForgeT.HelmerT.LinW.PapadopoulosA.P.2009Organic fertilizers for greenhouse tomatoes: Productivity and substrate microbiologyHortScience44800809

ZhengY.2016Root zone environment management in container crop production. Proc. for the Veg. potato greenhouse small fruit & Gen. session Mid-Atlantic Fruit & Veg. Convention Hershey PA

Article Information

Google Scholar



All Time Past Year Past 30 Days
Abstract Views 185 185 185
Full Text Views 22 22 22
PDF Downloads 5 5 5