There are a handful of methods used to grow marijuana. Some of them are:
Soil or Soilless
Most people are familiar with this method to grow marijuana. Individual plants are grown in some form of potting soil and watered and fed by hand or some sort of automated drip system. Regarding soils, “soilless mixes” are very popular to use for growing marijuana. They are technically not regular soil, and are mainly composed of either peat moss or coconut fiber (coco).
*Tip: There is a great advantage to using soilless mixes instead of common potting soil due to their high amount of air retention and PH stability. Soilless mixes are generally “lighter” soils which plant roots can more easily grow and spread out, and allow the mix to go through wet/dry water saturation better, and plant feeding can be more precisely contolled.
Hydroponics is a very popular method used to grow marijuana whereby the plants are suspended in a nutrient rich and often oxygenated water solution. There is no soil used. There are many different styles of growing hydroponically, from rows of PVC piping with plants every foot or so, to large tables that get flooded with water and drained periodically, to large 5 gallon buckets circulating water with very large plants.
*Tip : Closely monitor solution PH, temperature, and PPM.
Aeroponics works by the plant is sprayed with a fine mist of nutrient rich and highly oxygenated water solution. Like hydroponics there is no soil used. There are many resources online to find more detailed information on growing marijuana aeroponically.
*Tip : Clean spray nozzles regularly and always maintain a clean and sanitary environment.
As more states and eventually the country legalize marijuana for all uses; medicinally, recreationally and industrially, there will likely be new novel processes and methods employed to grow it. Research and development should continue to further advance techniques that could improve yields & quality in the future.