adding some HID lights to greenhouse
 

We are commercial growers of hydroponic tomatoes. We grow them under plastic. We are thinking of adding some HID lights to supplement the limited sunlight we get in New England during the winter. Does anyone have any advice or experiences in terms of types of lights to get; metal halide sodium, agrosun, etc., height from plant, length of time to leave lights on, differences in yield, ir cooled v. water cooled, etc? Thanks. Mike

Hi Mike
For cost per watt you use metal halide or high pressure sodium. 400 watt or even better 1000 watt.
Greenhouse tomatoes are indeterminate which means they grow and produce fruits continually so they aren't affected by getting to much light. I would turn the lights on whenever it got to cool in the greenhouse like at night or on a cloudy day. The lights would do double duty. Give the plants light and heat.
Ron