when to start using hps light?

I have 2 autoflower seedlings. They sprouted about 3 days ago. I have them in red party cups of soil. I started them in root riot cubes. They both have a true set of leaves on them. The humidity has been very low in my grow box its around 25%. So I have been using plastic baggies on them for a humidity dome. I been using 3 26w 6500k cfls on them for the light. I have a 150w hps that I wanna use on them soon. So I wanna know if I can start the hps on them now or wait a few more days till they get alittle bigger? How high above should I have the hps if I do use it?

You can start them now IMO. Just watch the canopy temp. I would start at a couple of feet and move it down slowly monitoring the heat.

Your still going to use the cfl's as well right?

waterdawg said:

You can start them now IMO. Just watch the canopy temp. I would start at a couple of feet and move it down slowly monitoring the heat.

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ok thank you for the reply.