Lights, Filters, and growing.

I want to do a small setup.

What are ballasts exactly and do i need them to do a cfl grow? should i just get a bulb and a socket and plug it in the wall socket or do i need the ballast for a cfl light.

What light spectrum do i need for veg + flowering. 6500k?? i got lumens covered.

For the filter i will use a diy carbon filter. How often does it need to be replaced?

Since i dont want to plant to be too tall. do i do a 20/4 light cycle until its my desired height and then quickly switch to 12/12 or gradually switch down by 2 hours every 2 days until 12/12.

thanks

ballasts exist to regulate the current for Lights, however CFL's are self ballasted, so no need for them.

6500K is good for veg, 2700K for Flowering.

Carbon Filters usually last about 9 months (ish)

you can do anywhere from 18/6>24/0(18/6 promotes better root growth, 24/0 promotes slightly faster veg growth) until the plant is half to a third of the size you want your final plant, they will double/triple in size during flowering

sweet thanks. so do anything inbetween 18/6 and 24/0 for vegging. than once i get about third of half of the height i start my 12/12.

thanks alot man.