The plant stops producing it when it reaches a certain species-specific age and flowering begins regardless of photoperiod. Often this is a synthetic brown foam polymer, but glass wool and coco fibre have been used. Even if they are still beneath the soil, you can go ahead and turn on your grow light.  Source: <a href=https://www.albanesecerchi.it/2013/06/12/hashish-seeds-market-dimension-share-development-forecast-2031/>https://www.albanesecerchi.it/2013/06/12/hashish-seeds-market-dimension-share-development-forecast-2031/</a>