Botanic Glass

From Rebirth of the Night Wiki

Botanic Glass is a block used for building structures similar to greenhouses. These enclosures allow crops to grow in any season, including winter. For a crop to receive this effect, botanic glass must be within 7 blocks above the crop block. Crops do not grow naturally under Botanic Glass if too far underground, but they will still be able to be grown with bone meal if provided enough lighting.

If hemp is to be grown underground, they will also need redstone-powered light blocks above the greenhouse glass.