Some of New Zealand's experimental commercial hemp crops are approaching 4m in height, says one of the researchers.
Hemp Industry Association research team leader Mac McIntosh, of Wellington, said that on most of the experimental sites the hemp was growing magnificently.
The crop of Motueka grower Steve Burnett had reached 3.35m
high.
Mr McIntosh said the success of a crop was not necessarily related to height, even though it looked likely some would grow higher than 4m.
Key issues would be the timing of seed production, the seeds' viability, how crops could be harvested efficiently and how they could be processed and marketed.
The crops appeared to have grown well in all sites except one, where it might have been affected by flooding.
So far there appeared few variations between the cultivars, although Kompolti/Uniko was the tallest, allowing for varied planting dates.
Pests, particularly the Australian passion vine hopper, had attacked plants in North Island sites and in the Tasman district but no serious damage had been done and honey bees appeared to be attracted to the pollen.
Cannabis cultivation was declared illegal in New Zealand in 1933, but last August the Government issued 11 licences to grow industrial hemp.
It is the same plant species, cannabis sativa, as the illicit drug crop but is bred for a very low level of the narcotic tetrahydrocannabinol (THC).
The THC level is less than 0.35 per cent of the dry weight of the plant.
This level is 10 to 20 times lower than that found in illicit cannabis cigarettes and health officials say it would not give anyone consuming it a "high".
- NZPA