Cannabis Cultivation Research Library

Authors: Yousoon Baek, Heather Grab, Chang Chen

14(3):414

Study plant: Two cannabinoid-type hemp cultivars (‘Hempress’ and ‘Wild Bourbon’)

Freshly harvested flower from two hemp cultivars was dried three ways (hot air at 75 °C, ambient air at 25 °C, or freeze-drying) and then cured in different containers. Hot air took the flower from 77% to 6% moisture in 8 hours and cut yeast and mold counts by up to 99%. Ambient drying took a week and freeze-drying a day. Total cannabinoids didn’t change significantly with drying or curing method, though some acid cannabinoids converted to their neutral forms. The authors favored hot-air drying followed by glass-jar curing.

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Authors: Ashleigh Ahrens, David Llewellyn, Youbin Zheng

13(3):433

Study plant: Two high-THC cultivars grown indoors to commercial maturity

Building on their earlier screening work, the researchers grew two high-THC cultivars to commercial maturity under either 12-hour or 13-hour days. The 13-hour plants produced at least 35% more total flower, far more than the roughly 8% extra daily light would explain, with cannabinoid concentrations unchanged or higher. One cultivar started flowering about 1.5 days later under 13 hours.

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Authors: Patrick Yawo Kpai, Oluwafemi Adaramola, Philip Wiredu Addo, Sarah MacPherson, Mark Lefsrud

15:1501484

Study plant: Cannabis in a hydroponic system, vegetative stage only

Using the same response-surface approach as earlier flowering-stage work, McGill University researchers varied nitrogen, phosphorus and potassium for vegetative cannabis in a hydroponic system. Nutrient interactions mattered: the effect of one nutrient depended on the levels of the others. Balancing growth against nutrient-use efficiency, they recommend about 160–200 mg/L nitrogen, 30 mg/L phosphorus and 60 mg/L potassium for the vegetative stage.

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Authors: Liam Buirs, Zamir K. Punja

13(6):786

Study plant: Review focused on high-THC cannabis grown in greenhouses

This review lays out an integrated plan for managing greenhouse cannabis diseases, including root rots (Fusarium and Pythium), bud rot (Botrytis), powdery mildew and hop latent viroid, at each stage from mother plants through cuttings, veg and flower. It stresses disease-tolerant genetics and pathogen-free stock plants, combined with sanitation, irrigation management, monitoring and climate control.

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Authors: Nimrod Brikenstein, Matan Birenboim, David Kenigsbuch, Jakob A. Shimshoni

7(1):111–118

Study plant: One commercial medical hybrid chemovar (Gen12)

Using a commercial hybrid chemovar (Gen12), the researchers compared trimming before versus after drying, and light versus aggressive trimming before drying, then measured cannabinoids and terpenes. A light trim before drying gave the highest cannabinoid concentrations, while trimming after drying preserved the most terpenes. All buds were dried under the same controlled conditions identified in the team’s earlier drying research.

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Authors: Matan Birenboim, Daniel Chalupowicz, David Kenigsbuch, Jakob A. Shimshoni

13(7):992

Study plant: One high-THCA chemovar, stored for four months after harvest

A high-THCA chemovar was sprayed with hexanoic acid before harvest (or left untreated), then dried, cured and stored for four months with or without vacuum sealing. THCA fell by 4–23% during storage, with the smallest loss in plants that received both the pre-harvest spray and vacuum storage. The spray protected monoterpenes more than vacuum storage alone, and treated plants had higher levels of some cannabinoids at harvest.

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Authors: Matan Birenboim, Nimrod Brikenstein, Danielle Duanis-Assaf, Dalia Maurer et al.

13(7):1049

Study plant: Two medicinal chemovars (a high-THC ‘240’ and a hybrid ‘Gen12’)

Two chemovars were dried in controlled-atmosphere chambers with different gas mixes, including nitrogen-rich and low-oxygen blends, and compared with traditional drying. The chambers cut drying and curing time by at least 60% while preserving terpenes. Traditionally dried buds were heavily infested with Alternaria mold and showed some Botrytis. The best gas mix differed by chemovar and by terpene type.

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Authors: Luke L. MacLaughlin, Mason T. MacDonald

6:42

Study plant: Dried flower from five cultivars grown at a licensed facility, canned and stored for 74 days

Dried flower from five cultivars was canned either under nitrogen (about 4% oxygen) or ordinary air, then analyzed for 17 cannabinoids and 61 aroma compounds over 74 days. Nitrogen packaging made no significant difference to total cannabinoids or total volatile terpenes, though it shifted some individual compounds. Monoterpenes declined sharply in both treatments during storage.

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Authors: Tyson James Peterswald, Jos Cornelis Mieog, Razlin Azman Halimi, Nelson Joel Magner, Amy Trebilco, Tobias Kretzschmar, Sarah Jane Purdy

12(5):1061

Study plant: Three medicinal cannabis varieties, including the CBD variety Cannatonic

Three medicinal cannabis varieties were flowered under nine different photoperiod schedules, including longer days (such as 14 hours light, 10 dark) and gradually changing day lengths, instead of the standard 12/12. In the CBD variety Cannatonic, every schedule that started flowering at 14/10 raised CBD concentration and increased total CBD yield by 50–100%. The authors conclude that 12/12 is not optimal for every line.

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Authors: Ashleigh Ahrens, David Llewellyn, Youbin Zheng

12(14):2605

Study plant: Clones of ten drug-type cultivars in a growth chamber for 3–4 weeks

Clones of ten drug-type cultivars were grown for three to four weeks under six photoperiods to test whether days longer than 12 hours still trigger flowering. All ten cultivars began flowering under every photoperiod up to 14 hours. For some cultivars, early flowering measures peaked somewhere between 12 and 13 hours of light.

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Authors: Danilo Crispim Massuela, Sebastian Munz, Jens Hartung, P. M. Nkebiwe, Simone Graeff-Hönninger

14:1233232

Study plant: CBD-dominant medicinal cannabis grown indoors

CBD-dominant medicinal cannabis was flowered on mineral or organic fertilizer at three strengths (80, 160 and 240 mg/L nitrogen) to test whether deliberately underfeeding in flower can save fertilizer. Underfed plants yielded less flower, but higher CBD concentrations made up most of the difference: they reached 95% of the CBD yield with one-third less fertilizer. The organic fertilizer was taken up and used less efficiently than the mineral one.

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Authors: Robert L. Geneve, Evan W. Janes, Sharon T. Kester, David F. Hildebrand, Derrick Davis

2(4):415–427

Study plant: Two industrial oilseed hemp cultivars (‘Georgina’ and ‘Victoria’), lab germination tests

Researchers germinated hemp seed at constant temperatures from 3 °C to 42 °C to map how warmth affects sprouting speed and success. Seeds germinated best and fastest between roughly 19 °C and 30 °C, with a calculated optimum near 29.6 °C, a floor around 3.4 °C and a ceiling around 42.6 °C. Priming the seeds before sowing made them sprout faster but did not raise the final germination percentage.

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Authors: Jia W. Tan, Sharon T. Kester, Kai Su, David F. Hildebrand, Robert L. Geneve

2(4):407–414

Study plant: Low-germinating industrial hemp seed lots, lab germination tests

The team worked with hemp seed lots that germinated poorly and tested two rescue techniques: priming (a controlled pre-soak) and carefully removing the hard outer shell. Both sped up early germination, but removing the shell did more for the final result, raising germination in weak seed lots by about 38% on average compared with intact seed.

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Authors: Lauren E. Kurtz, Lillian N. Borbas, Mark H. Brand, Jessica D. Lubell-Brand

57(12):1576–1579

Study plant: Two CBD-type cultivars (‘Abacus’ and ‘Wife’) grown in a greenhouse

This study compared plants grown from lab tissue-culture “microcuttings,” regular stem cuttings from mother plants, and “retip” cuttings taken from new shoots on recently tissue-cultured plants. Retip cuttings rooted at 76–81% with no rooting hormone, similar to what hormone-treated stem cuttings achieve. Once the tissue-culture plants were given one extra week of vegetative growth, all three propagation methods produced equivalent plants and flower weight.

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Authors: Avia Saloner, Nirit Bernstein

13:830224

Study plant: Medical drug-type cannabis fed 200 mg/L nitrogen in five ammonium/nitrate ratios

Medical cannabis was fed the same total nitrogen (200 mg/L) supplied in five ratios of ammonium to nitrate, from 0% to 100% ammonium. Raising the ammonium share generally hurt the plants: flower yield, cannabinoids, terpenes and photosynthesis were highest on nitrate alone, and yield fell 46% as ammonium rose from 0% to 50%. Moderate ammonium levels (10–30%) caused little harm.

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Authors: Nadav Danziger, Nirit Bernstein

13:713481

Study plant: One drug-type medical cultivar at 1 or 2 plants per square meter

A drug-type medical cultivar was grown at one or two plants per square meter, combined with four plant-architecture treatments. Denser planting increased yield per area but made cannabinoid concentrations less uniform across the plant, and spacing interacted with how the plants were shaped. The effect was cannabinoid-specific: some compounds varied more by bud position than others.

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Authors: Danilo Crispim Massuela, Jens Hartung, Sebastian Munz, Federico Erpenbach, Simone Graeff-Hönninger

11(1):140

Study plant: One CBD-dominant (chemotype III) medicinal genotype grown indoors

A CBD-dominant (chemotype III) genotype was harvested at four points between weeks 5 and 11 of flowering and grown with three pruning approaches: topping, removing side shoots, or no pruning. Flower weight kept increasing over time while CBD concentration stayed flat, so total CBD yield peaked at week 9. Top buds had higher CBD (9.9%) than middle (8.2%) or lower (7.7%) buds. Topped plants trended toward higher yields, though not significantly more than unpruned plants.

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Authors: Pabitra Chandra Das, Alec Roger Vista, Lope G. Tabil, Oon-Doo Baik

9(8):364

Study plant: Review of post-harvest research on cannabis and hemp

A technical review of what happens to cannabis after harvest: how the major cannabinoids form, and how trimming, drying, curing, packaging and storage affect them. It covers drying science such as water activity and moisture equilibrium, plus newer pre-treatments like microwave heating and cold plasma. The authors note that the common hang-drying method is inefficient and can produce inconsistent quality.

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Authors: Hebah Muhsien Sabiah AL Ubeed, Ronald B. H. Wills, Jayani Chandrapala

27(5):1719

Study plant: Literature review of drying technologies for medicinal cannabis

This review surveys traditional and modern drying technologies for medicinal cannabis and how they affect the plant’s active compounds. It concludes that drying temperature, drying rate, the drying method and storage conditions afterward all shape what the final product retains, and that the quality of the harvested material also affects drying efficiency.

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Authors: Christiana J. Smith, Daniela Vergara, Brian Keegan, Nick Jikomes

17(5):e0267498

Study plant: Lab-test results from nearly 90,000 commercial cannabis samples across six US states

Analyzing cannabinoid and terpene lab results from nearly 90,000 commercial samples across six US states, researchers found a small number of distinct, recurring chemical profiles. Those profiles did not line up consistently with indica, sativa or hybrid labels, and some strain names were far more chemically consistent than others.

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Authors: Sean M. Campbell, Steven L. Anderson, Zachary T. Brym, Brian J. Pearson

16(7):e0249160

Study plant: Eight high-CBD hemp cultivars, cuttings rooted for 12 days in a climate-controlled room

Researchers rooted cuttings from eight high-CBD hemp cultivars across four propagation media and five commercial rooting hormones, then measured root number, length and mass after 12 days. The medium mattered most: rockwool far outperformed the other media. Any rooting hormone improved rooting 15- to 18-fold over none, but hormone strength and application method made little difference. Some cultivars simply rooted better than others.

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Authors: Victoria Rodriguez-Morrison, David Llewellyn, Youbin Zheng

12:646020

Study plant: Drug-type cannabis flowered indoors under sole-source LED lighting

Plants were flowered under a wide range of canopy light levels to see how intensity affects yield, potency and leaf photosynthesis. Dry flower yield kept rising in a straight line all the way up to 1,800 µmol·m⁻²·s⁻¹, even though individual leaves stopped gaining photosynthesis well below that level. Light level had no effect on cannabinoid potency and only minor effects on terpenes. The authors conclude that leaf-level measurements are a poor guide to whole-plant yield.

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Authors: F. Mitchell Westmoreland, Paul Kusuma, Bruce Bugbee

16(3):e0248988

Study plant: CBD-type medical hemp in growth chambers, three separate studies

Across three separate growth-chamber studies, researchers changed only the share of blue light (from 4% under HPS up to 20% under LEDs) and measured flower yield and cannabinoids. Yield dropped about 12% in a straight line as blue increased from 4% to 20%. Blue fraction had no significant effect on THC or CBD concentration. The authors argue that a fixture’s efficiency (light produced per watt) matters more than its color mix.

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Authors: Victoria Rodriguez-Morrison, David Llewellyn, Youbin Zheng

12:725078

Study plant: Two indoor drug-type cultivars (‘Low Tide’ and ‘Breaking Wave’)

Two indoor cultivars received daily supplemental UV from 287 nm LEDs at a range of doses throughout flowering. Total yield fell in one cultivar as the UV dose increased, and the share of yield coming from the top buds dropped in both. UV did not deliver any commercially meaningful increase in yield, cannabinoids or terpenes.

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Authors: Md. Jahirul Islam, Byeong Ryeol Ryu, Md. Obyedul Kalam Azad, Md. Hafizur Rahman, Eun Ju Cheong, Jung-Dae Lim, Young-Seok Lim

10(8):710

Study plant: 25-day-old hemp seedlings in an aeroponic system, 20 days of light treatments

Young hemp plants were grown aeroponically under ten LED spectra plus natural light for 20 days, and researchers tracked cannabinoids alongside markers of plant stress. A red-blue-green mix (R7:B2:G1) gave the highest CBD with relatively low stress. THCA behaved most like a stress marker, while CBD and THC showed little link to light-induced stress.

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Authors: Lewys Bevan, Max Jones, Youbin Zheng

12:764103

Study plant: One high-THC cultivar in deep-water culture

A high-THC cultivar was flowered in deep-water culture across combinations of nitrogen (70–290 mg/L), phosphorus (20–100 mg/L) and potassium (60–340 mg/L). Flower yield peaked at about 194 mg/L nitrogen and 59 mg/L phosphorus, with more or less of either lowering yield. Potassium had no measurable effect on yield across the range tested.

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Authors: Nadav Danziger, Nirit Bernstein

10(9):1834

Study plant: Large (about 2.5 m) CBD-dominant medical cannabis plants

Large medical cannabis plants (about 2.5 m tall) received eight shaping treatments, including defoliation, removing lower branches and leaves, removing branches, and pruning, to see which made cannabinoid levels more uniform from top to bottom. Pruning twice produced the highest cannabinoid yield per plant, while removing the primary branches cut it drastically. Defoliation alone did not raise cannabinoid yield.

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Authors: Zamir K. Punja

77(9):3857–3870

Study plant: Review of diseases reported in North American cannabis and hemp production

A review of the diseases currently affecting cannabis and hemp production in North America, covering newly characterized pathogens reported from 2017 to 2020, including Botrytis bud rot, powdery mildew and hop latent viroid. It emphasizes sustainable control using biological products and reduced-risk options, and notes that indoor and greenhouse crops share more diseases with each other than with field-grown plants.

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Authors: Lisa Burgel, Jens Hartung, Simone Graeff-Hönninger

6(4):62

Study plant: Two CBD-rich genotypes in pots, indoor cultivation

Two CBD-rich genotypes were grown indoors in pots of peat, peat with 30% green fiber, or coco coir. Responses depended on the genotype: one produced substantially less flower in coir and in the fiber blend than in peat, while the other did well in the peat and fiber blend. CBD content stayed the same regardless of substrate.

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Authors: Deron Caplan, Mike Dixon, Youbin Zheng

54(5):964–969

Study plant: One medical cannabis cultivar, drought stress applied in week 7 of flowering

Starting in week 7 of flowering, researchers withheld irrigation from one group of plants until they reached a defined wilting threshold, which took 11 days, then compared them with normally watered plants. The drought-stressed plants had higher THCA and CBDA concentrations without losing harvested dry weight.

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Authors: Deron Caplan, Jonathan Stemeroff, Mike Dixon, Youbin Zheng

98(5):1126–1132

Study plant: Drug-type cannabis stem cuttings, 12-day rooting trial in a growth chamber

This trial tested common cloning habits side by side: how many leaves to leave on a cutting, whether to trim the leaf tips, whether the cutting came from the top or bottom of the mother plant, and a synthetic IBA rooting gel versus a willow-extract gel. Trimming leaf tips cut rooting success from 71% to 53%. Cuttings with three leaves grew better-quality roots than two-leaf cuttings, and the IBA gel outperformed the willow product.

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Authors: Gianmaria Magagnini, Gianpaolo Grassi, Stiina Kotiranta

1(1):19–27

Study plant: Cannabis clones grown under one HPS and two LED spectra

Clones were grown under high-pressure sodium (HPS) and two LED spectra to compare plant shape and cannabinoid content. Plants under HPS grew taller and produced more flower dry weight than under either LED. The light sources shifted the mix of cannabinoids, with the LED richest in blue and UV-A giving the highest CBG, but total cannabinoid yield per plant was similar across all three.

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Authors: Deron Caplan, Mike Dixon, Youbin Zheng

52(9):1307–1312

Study plant: Medical drug-type cannabis in two commercial coir mixes, walk-in growth chamber

Plants were fed a liquid organic fertilizer (4.0-1.3-1.7) at five rates during vegetative growth in two coir-based mixes that differed in how much water they hold. The two coir mixes performed the same. Yield, cannabinoid content and growth were best at a rate supplying about 389 mg/L nitrogen during veg, which gave 1.8 times the yield of the lowest rate.

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Authors: Deron Caplan, Mike Dixon, Youbin Zheng

52(12):1796–1803

Study plant: Medical cultivar ‘WP:Med (Wappa)’ in two commercial coir mixes, walk-in growth chamber

In this follow-up flowering trial, a liquid organic fertilizer (2.0-0.87-3.32) was applied at five rates to plants in two coir mixes. Feeding more increased growth and yield but diluted THC, THCA and CBGA concentrations. In the drier of the two coir mixes, rates supplying 212–261 mg/L nitrogen best balanced flower yield against cannabinoid yield.

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Authors: Judith K. Booth, Jonathan E. Page, Jörg Bohlmann

12(3):e0173911

Study plant: Genetic and chemical analysis of cannabis plants, including the hemp cultivar ‘Finola’

By analyzing cannabis genetic data alongside resin chemistry, the researchers identified about 30 terpene synthase genes, the genes that build cannabis aroma compounds, and characterized the enzymes behind several major terpenes. These include limonene (lemony), myrcene (earthy) and beta-caryophyllene, a terpene that also interacts with cannabinoid receptors.

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Authors: Suman Chandra, Hemant Lata, Ikhlas A. Khan, Mahmoud A. ElSohly

17(3):291–295

Study plant: Leaves of four high-THC varieties, short-term gas-exchange measurements

Leaves of four high-THC varieties were measured at roughly ambient (390 ppm) and elevated (545 and 700 ppm) CO₂. Under elevated CO₂ the leaves partly closed their pores and lost less water, which raised their water-use efficiency.

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Authors: Suman Chandra, Hemant Lata, Ikhlas A. Khan, Mahmoud A. ElSohly

14(4):299–306

Study plant: Leaves of a high-THC Mexican variety, measured in a leaf chamber

Using a leaf chamber, researchers measured photosynthesis and water-use efficiency in a high-THC variety across light levels up to 2,000 µmol·m⁻²·s⁻¹, temperatures from 20 °C to 40 °C, and CO₂ from 250 to 750 ppm. Photosynthesis and water-use efficiency rose with light at the cooler temperatures (20–25 °C), and temperatures above about 30 °C reduced photosynthesis. It remains a widely cited baseline for cannabis environment targets.

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