When should I switch from Cfls to Hps??

Regarding the lights, it depends on personal pref and also your growing surroundings...some people actually do it from start to finish under a HPS light.

I would personally, switch them to the HPS when i want to switch to 12/12..never used those nutes before mate, but i tend to start on 2nd/3rd week (slightly less than 1/4 of recommended and work my way up).

 

If you want to stretch the plant out vertically, switch to hps sooner (maybe 3-4weeks in). The red spectrum of the hps, along with its increased distance away from the plant, will cause it to reach more so than the blue spectrum of the cfl. I switched a plant to hps at the start of flowering though and had no problems; I just wonder how much bigger she would have been if she was under hps the whole time. Now I run hps all the time and supplement it with cfls in the lower areas that don't receive a lot of light from the top. As for nutes on the organic grow, it's never too early to begin feeding the soil with a compost tea.

 

I usually start my seedlings right under a 430watt HPS agrosun/son-agro, and other times even under a 1,000 watt HPS... depends what season it is, and which light/s I'm running in the veg chamber.


Any time is a good time to increase the lumens, if you want a shorter veg period, or if you want more growth to multiply and occur, during any given period of time.

It's just a matter of height adjustment versus how delicate/small the plants are... want stretch? You'll get more of it, plus healthier and thicker stalk growth (that means more bud support and growth!) with a more intense light, placed higher above the canopy... more light, just means you can pull in a much larger quantity of bud, in the same or less time.