Quote Originally Posted by dylan
The plant dies in the fall and drops seeds, which grow into new plants in the spring.
Some of the seed germinates in the Autumn that it drops, especially if you get rains before the frosts hit. Most seedlings die in the first cold snap, but those that survive the winter really boom once the weather warms.

From what my father told me about hemp growing in Queensland during the last century, hemp can be grown for multiple seasons. He grew up on a farm which inter cropped hemp with sugar cane, until demand for sugar outstripped hemp and the product was eventually prohibited.

Granted, you can't really draw any parallels between growing for fibre production and growing for resin production, but maybe that's where these sorts of ideas originate?