Well, we need more info in order to answer the question. What is the strain, is it in week 8 of it's life or week 8 of flowering? How do the trich's look? Generally peope like to see about 30% amber trichs to signal time to harvest.
Although not an expert the general concesus seems to be when 75% of the trichomes (crystals) are turned to an amber color. As well there needs to be a 2 week stop of nutes before harvesting to keep all the junk out your buds.
i would like to get a hps 100w light. but wil the plant still grow if i just put the light into a side socket in a closet? or does the light need to be above the plant? will they grow horizontally if the light is horizontal?
Some HID lights are orientation specific, IE. they are design to run either vertically or horizontally. The smaller HPS lights (outdoor illumination lights) might run in either orientation, IDK. However, plants use the sun and the sun shines down on plants from above, so your primary illumination should be above the plants IMHO. Plants won't grow sideways if the light is off to the side, what they will do is develop more on the side with the light, so you get a lopsided plant. For best results, place the light above your plant, and put Mylar on each side of the plant to reflect light back toward the leaves and lower branches. Oh, with regard to Trichomes; the more amber the trichs the more of a couchlock high you get. The more milky the trichs the more of an uplifting, soaring high you get.