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24 hours of light

Gummy Bear

New Member
If there are plants that are in veg and a plant in flower (but almost done) how much harm is done by exposing the vegging plants to the HPS light for 12 hours and then switching to the MH for 12 hours while the flowering plant is removed to a dark area?

Only have one fixture. Its a 400 watt MH/HPS convertable system. They are all in there together during the day under the HPS and then when it's time for the 12 hours of dark the big one is removed and the MH is plugged in. This whole cycle starts over in the morning.

Is this really bad? I am aware of the traditional lighting requirements and the spectrum of light each one puts out and the light spectrum recommendations for vegging and flowering. I just do not have two fixtures.

If one light had to be used the whole time would you recommend the MH or the HPS? :hmmmm:


Well-Known Member
If I had to pick one it would probably be the HPS. You can get by vegging with it because veg. periods are usually so short, and the bud production from an HPS is second to none.

Gummy Bear

New Member
Thanks again RooRman!!!

This is my first experience using the HPS and I can not wait to see if it pays for itself.

The growers here seem to swear by the MH and HPS systems, so I am sure the results will be amazing.

It's only 400w, but that should be plenty for what I need.

Thanks again.


New Member
I would also stick with the hps. Switching bulbs daily would not be fun and sounds like a recipe for disaster. You can destroy a switchable ballast trying to ignite a mh when its set for hps or vise versa and people do make mistakes.
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