I grow in the greenhouse but a member of one of my orchid societies asked for some guidance. He wants to start growing in a basement using 600 watt HPS lighting. It is completely dark down there with only one small window which does not go outside but rather opens into a small sun room that is heated during the winter. Upon doing some research I found out it was cheaper to run 2 600 watt lights rather then a single 1000 watt light. In doing my research most of the information that I found out was in regard to growing marijuana in small spaces. They keep talking about having an intake and outake fans to exchange and bring in fresh air. Well I assume this was do to the fact they were growing in very small confined areas. I assume this wouldn't be necessary if the grow space was in the corner of the basement that was all opened. So am I correct? Please school me.

One of my previous neighbors used to grow plants under lights in his basement with only one small window. I dont remember seeing any intake and outake fans so I think heat wasnt a big issue.

Hi Bob,

I grew in a basement for almost three years before going to a greenhouse this past fall. Eventhough my basement was large I still put a fan in the window. It was one of the duel fans that had an intake and out-take. As you know, fresh air is always welocmed by the plants and I believe the air exchange in the basement would always be a benefit. I had the fan on a timer.

Christian

I have a set up up almost identical. Basement room, no window except one that is actually under our sunroom--therefore no light or ventilation.

I have used this room for 6 years using 3 flora carts and a 400 watt HPS on a light mover. The plants seem to do better and better each year. Before that I had a similar setup at my old home for over 10 years.

I have a small humidifier which is set at 60% and the lights are on timers. A small 9 inch fan oscillates whenever the lights are on.

I have sealed off the room using plastic sheeting so that the humidity doe not adversely affect the rest of the house. However with the fan running there are no problems with the atmospere. I have no ventilation to outside of the room except when entering and leaving the room to water etc.

I also find that temperture wise this set up works well. The heat from the lights alone brings the temp to about 75F in winter and 80-85F in summer during the day and the temp naturally drops to about 58-62F in winter and 65-68 in summer.

Hopes this helps. Best of success to your friend.

Ed

I would encourage your friend to look into using metal halide...light output is not as strong as HPS but it is a much better spectrum for plant growth. There is a new type of lamp, ceramic metal halide (CMH) that is used with HPS ballasts that is supposed to have higher output than standard metal halide.

As to the exhaust issue, yes it would be important for fresh air circulation. Heat shouldn't be a problem in that kind of area and like Ed the light on/light off temperature change is good for orchids.

I ran into my ex neighbor yesterday and asked about his setup.He has no exhaust fans and the plant area in his basement is now sealed to keep the humidity in.