Table 1.

Drying techniques for medicinal Cannabis buds.

Drying Technique	Drying Conditions/Procedures	Advantages and Disadvantage	References
Hot Air Drying	The plant materials were hanged on either string lines, wire cages, or static wires upside-down to allow for air circulation and uniform drying by control system has been set between 18–21 °C, relative humidity at 50–55% and air circulation using a small fan under these controlled conditions. Trimmed flowers take only 4–5 days, but the whole plant takes up to 14 days.	A simple technique, but required regularly maintain optimal conditions.	[59,75,76,77,78]
Oven Drying	Buds were hanging upside down in the oven and oven must be preheated at 37 °C for 24 h to prevent decarboxylation for Phyto cannabinoids	A simple technique, but under optimal conditions and difficult for commercial production.	[75,78,79]
Microwave-assisted hot air-drying	Samples were dried by applied volumetric heating and creating a temperature gradient and standard microwaves frequency set at 915 MHz and 240 W to maintain high-quality medicinal cannabis	An advanced technique, but under optimal conditions.	[80,81,82]
Vacuum Freeze-Drying	Vacuum freezing the cannabis bud by reducing the temperature to approximately −40 °C before drying the buds to retain a high quality of phytochemicals.	Quite effective and most suitable advanced technique, but prohibitive operational cost.	[83,84,85,86,87]
Microwave-Assisted Freeze Drying	Circulates cold, dry air over the frozen material at a temperature below −40 °C to −45 °C, pressure at 100 Pa, microwave frequency 2450 MHz.	An advanced technique, but under optimal conditions.	[76,88,89,90]