The proposed law if NZ votes to legalise recreational cannabis use says:
ANY PERSON WILL BE ALLOWED TO GROW TWO PLANTS FOR PERSONAL USE, TO A LIMIT OF FOUR PER HOUSEHOLD
So how many joints could be produced from home?
Obviously these numbers are very general because grow techniques vary, but conservatively one marijuana plant in a hydroponic indoor set-up could produce a harvest about every 110 days and from that harvest the grower would get between 198 grams and 311 grams of buds (Median 254.5grams) and also about 198 grams to 311 grams of leaf (Median 254.5grams). In NZ the buds are desired for smoking because they have the highest amount of THC and the leaf is also smoked. However now in the U.S with legal states whether medicinal or recreational Leaf is now most commonly used by individuals to make concentrated THC by way of Butane Hash Oil (extremely high potency THC), which is also on a side note causing a lot of explosions and fires in the U.S.
Therefore annually one plant could be producing a median of 1,527 grams smokable product per annum.
We estimate that the mean weight of marijuana in a joint is 0.32 g (95% Bayesian posterior interval: 0.30–0.35).
So even if you were generous and said that .5 grams per joint then essentially one plant would yield as a Median 3,054 smoking joints per annum equivalent to 8.36 joints per day.
NZ legislation is proposing up to 4 plants can be home-grown
4 plants the median would be 12,216 smoking joints per year – equivalent to 33.46 joints per day over the year of the psychoactive substance THC.
And they call it “control”. Go figure!