There are several sources that you can consult for technical information on growing herbs in an urban hydro farm in cold weather conditions. Some options include:
Extension resources: Many universities and other organizations have extension programs that provide research-based information on horticultural practices, including hydro farming in cold weather. You can search for extension resources specific to your location to find relevant information on growing herbs in a hydro farm.
Commercial hydroponics suppliers: Many commercial hydroponics suppliers offer technical information and support for hydro farming, including information on growing herbs in cold weather. You can search online or contact suppliers in your area to access this type of information.
Professional organizations: Professional organizations such as the Association for Vertical Farming or the International Association of Horticultural Producers may have resources and information on growing herbs in a hydro farm, including in cold weather conditions.
Online forums and communities: There are many online forums and communities dedicated to hydroponics and urban farming, where you can find information and advice from other farmers and experts.
It may also be helpful to consult with a local expert or seek advice from a professional grower or consultant with experience in hydro farming in cold weather conditions.