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Prohibited plants

Offences involving prohibited plants

The cultivation or possession of prohibited plants, such as cannabis, is an offence.

It is an offence to:

  • cultivate
  • knowingly take part in the cultivation of
  • possess
  • supply

a prohibited plant.

What is included?

Cultivation is defined to include sowing seed, planting, tending, nurturing or harvesting. Watering a plant, shading it from the sun, picking the heads off a friend's plant, even watering ungerminated seeds, all come within the definition of cultivation. Possession of plants is also an offence under the same section and with the same maximum penalty as for cultivation. A charge of possession of prohibited plants would be laid where there was no evidence of any act of cultivation (such as planting or watering), but there was evidence of possession (again, requiring proof of knowledge and custody or control) of the plants.


The penalty categories for cultivating cannabis depend on the number of plants, not their gender or size. Cultivating a hundred seedlings that can fit into a baking tray is treated the same as cultivating a hundred mature female plants. Having 250 seedlings is regarded as more serious than having five big plants, even though the weight of the five big plants may be many times greater. Higher penalties apply to offences involving the cultivation, supply and possession of a 'commercial quantity' of prohibited plants.

Defences to cultivation

It is a defence to a charge of cultivation of a prohibited plant if the accused can establish that they did not know the plant was a prohibited plant. The prosecution may rebut the accused's evidence by bringing, with leave of the court, evidence of any previous convictions.

Hydroponic cultivation

It is an offence to participate in the 'cultivation by enhanced indoor means' of five or more plants for a commercial purpose. 'Commercial purpose' means intending to sell or believing that another person intended to sell. [Note that the offence of (outdoor) cultivation of cannabis in section 23 (1)does not involve any requirement to prove a commercial purpose.]

The offence requires the cultivation to:

  • be inside a building or structure and
  • involve growing the plant in nutrient enriched water or applying artificial light or heat or suspending the roots and spraying them with nutrient solution and
  • involve five or more plants and
  • be done with the intention to sell (or the belief that another person intends to sell) the cannabis produced (if there are fewer than 50 plants).

If there are more than 50 plants the prosecution does not have to prove a 'commercial purpose' (that is, the intent to sell).

Exposing a child to indoor cultivation

It is an offence to cultivate 'a plant' (note the singular) by enhanced indoor means and 'expose a child' to the cultivation process or to substances stored for use in cultivation. It is a defence if the defendant can prove that the exposure did not endanger the health and safety of the child. For the purposes of this provision, a child is a person under 16.