The Effect of Chemical and Granular Organic Fertilizer with Hormone Mixed Formula (Ho) and Chemical Fertilizer on Growth of Cannabis (Cannabis Sativa L.) in Outdoor Condition

This research was to study the effect of chemical and granular organic fertilizer with hormone mixed formula (HO) and chemical fertilizer to improve the vegetative growth of cannabis in outdoor conditions. The experiment was conducted in pots under natural conditions, using a Completely Randomized Design (CRD) with 13 treatments of fertilizer applied with 6 replications, totally 78 pot plants. The pot size is No.17 with 12 Kilograms of growing media per pot, The treatments included: T1 - No fertilizer (Control), T2 - Chemical fertilizer 25-7-7 (50 kg/rai, 1 rai = 0.16 ha), T3 - Chemical fertilizer 25-7-7 (100 kg/rai), T4 - Chemical fertilizer 16-8-8 (50 kg/rai), T5 - Chemical fertilizer 16-8-8 (100 kg/rai), T6 - Chemical fertilizer 15-15-15 (50 kg/rai), T7 - Chemical fertilizer 15-15-15 (100 kg/rai), T8 - HO-1 (50 kg/rai), T9 - HO-1 (100 kg/rai), T10 - HO-2 (50 kg/rai), T11 - HO-2 (100 kg/rai), T12 - HO-3 (50 kg/rai), and T13 - HO-3 (100 kg/rai). The test plant was 25-day-old Hang Kra Rok Phu Phan ST1 cannabis seedlings. The study was conducted from November 2022 to June 2023 in Moo 7, Wang Nok Aen Sub-district, Wang Thong District, Phitsanulok Province. Data were analyzed using ANOVA and means were compared using DMRT at 95% confidence level.The experimental results revealed that 1) Nutrient analysis: HO fertilizers (HO-1, HO-2, HO-3) contained moderate levels of N-P-K, high levels of secondary (Ca-Mg-S) and micronutrients (Fe-Cu-Zn-Mn), whereas chemical fertilizers lacked these secondary and micronutrients. HO fertilizers had slightly acidic pH (6.5-6.7), favorable for nutrient uptake. 2) Growing media analysis: before the experiment analysis showed high N-P-K and Ca-Mg levels, very low S, and low micronutrient levels. After the experiment, N decreased while other nutrients increased. HO treatments improved pH more than chemical fertilizers. 3) Water retention: HO fertilizers, especially T13 (HO-3, 100kg), significantly improved water retention capacity (from 26.1% to 29.9%). 4) Chlorophyll content: Increased with plant age, with T13 showing significantly higher levels at 30, 45, and 60 days after planting. 5) Growth parameters: Plant height, stem diameter, leaf number, canopy size, and branch number were highest in T13, T12, and T11, respectively, showing statistically significant differences. 6) Growth pattern: Chemical fertilizers promoted faster initial growth (first 30 days), while HO fertilizers demonstrated superior growth from 45-60 days. T13 (HO-3, 100kg) was identified as the most effective fertilizer for cannabis cultivation under outdoor conditions, demonstrating significantly greater growth than other treatments. The diverse nutrient composition and soil-enhancing properties of HO fertilizers contributed to more sustained cannabis growth compared to conventional chemical fertilizers.