Medicinal Cannabis

Medicinal cannabis is becoming a growing part of the agriculture industry in the UK.

Cannabis requires a particular way of growing and there are some similarities and differences between growing cannabis and growing vegetables/herbs indoors.

Just as with vegetables, humidity control is an important factor that needs to be considered for indoor cannabis production. The amount of moisture in the air affects the transpiration rate of the plants, which refers to the amount of water lost by plants. Transpiration is responsible for moving water and nutrients from the root to other parts of the plant. However, when humidity levels are too high or too low, transpiration slows and curbs plant growth. The correct humidity level is therefore extremely important, anything outside of this ideal range will cause the stomata to close as a stress-induced response.

The ideal humidity for cannabis plants in seedling form is 70%, falling to 50%-55% while in flowering and vegetative form and reducing furthermore for the drying purpose to around 40-50%. These figures could differ depending on the genetics of the cannabis plant but with any drying process it is important not to dry too quickly so a gradual drying process is required.

Mould can be problematic for cannabis production so it is vital the correct humidity is adhered to as mould can spread quickly through the crop. If mould is present there is a risk the whole crop can be rejected as strict standards for medicinal cannabis need to be adhered to. The aim of the medicinal cannabis minimum quality standard is to ensure the consistency and quality of the products that medical practitioners prescribe to their patients.

With the range of equipment available to us, Humidity Solutions can design and install the complete humidity control system for the efficient, consistent production of medicinal cannabis.




4x: Flower Rooms – When buds appear (reduce rh to 55%) – 20C – 22C (never below 20C)


  • Vegativ stage (70% Max) – 25-27C first stage
  • 2 weeks after above stage started reduce to 50-55% rh
  • Ideally allow for 40-60% due to different genetics of Cannabis
  • Plants in here will vaporize 80% of water given in 24hrs
  • 1tr per day per plant = 800ml vaporized
  • 1,152 plants per Flower room – 4 rooms TOTAL
  • *Some genetics will use up to 1.5l per day (MAX)
  • Room = 22m X 4.8m X 4.2m
  • Heat/lights: 70,200w of cooling needed

X1: Mother room – (Same size as room above but will have different equipment)

  • 60-70% rh
  • 25-29C
  • Mother plants will get 2-3l/day (Again 80% given off to the space)
  • 50 Mother plants in this room
  • Some other plants in room (Clones) = estimated 6-15l day given off
  • Room = 22m X 4.8m X 4.2m
  • Heat/lights: 30,w of cooling needed

X1: Drying Room: – Plants moved into separate room

  • 40-50% rh moving up to 45-50%rh after a day
  • 18-20C
  • 40-50% of moisture from the plant is lost in day 1 of this process