Five grow questions. (2 X 400w HPS, Fox Farm medium and nutes, NL seeds)

I am going to begin my first grow in a few days. I just have a few questions. I have been searching this site and have found some answers but I would like direct answers from experienced growers.

1.) Do things like LST, supercropping, FIM, and topping increase yield substantially? If so, how much time will doing these things add to the grow time.

2.) Is it unheard of to grow without doing any of the things mentioned above?

3.) How many plants should I grow with two 400w HPS lights if I want to use the methods mentioned above? How many if I don't use them?

4.) How much will one Northern Lights plant yield if it is flowered at 16" without using any of the methods mentioned above under OPTIMUM conditions?

5.) How many square feet should my flowering room be if I'm using two 400w HPS lights?

1. ok LST super cropping and fim are COMPLETE PERSONAL PREFERENCE. I have seen valid results both using them and not using them. Where will you be growing? This will determine whether you need to use these techniques or not. For instance say you are growing SOG (sea of green method) on a couple shelves in a big cabinet. Then you would have a limited amount of vertical space and these techniques would be useful. taming the plant to produce more tops or cola's is only effective if you know how to tend to it when it starts to regrow. plants become top heavy, but beware I have seen that although you have 2 colas USUALLY (not all the time) they do not add up to the weight of the one top cola the plant will grow naturally.
2.SO no it is not unheard of. Unless properly shown https://www.rollitup.org/general-marijuana-growing/13820-fimming-topping-101-a-12.html it can damage your plants and decrease your yield.
3. again the answer to this question depends on how you plan to grow your plants. If you put 10 plants under 1 400watt the buds would be smaller as more plants are sharing the same light. But 6 plants evenly spaced at 2x3 would allow more light through (because you arent creating a dense canopy). I would suggest 12 plants under 2 400watt spaced 3x4. also look into a growing style called SCROG.
4. 2 ounces per plant is an OPTIMUM GOAL for a semi-new grower. That is kinda pushing it though (all depends on soil conditions, lights, fresh air, etc)
5. 5x5 or 4x4. I would suggest 5x5 and PROPER AIR CIRCULATION.

I hope I helped, I know its frustrating to get your questions answered with more questions so feel free to contact with any more.

Thanks for the answers. I have a 68" ceiling (wierd, I know), so I figure the biggest the plant could get (accounting for the pot and distance from light) is about 4 feet. Would twelve 4 foot plants be good under the two lights, or should I do more shorter ones?

here is my suggestion. I think you should flower them as soon as they hit 12-14 inches (preferably 12) when they look like they are pushing (growing exponentially, usually a week after you flower them) wait until they are 8-9 inches under your lights then erect a screen with spaces ranging from 1/2 to full inch. what this does is creates a "ceiling". MAKE SURE YOUR LIGHTS ARE NOT BURNING YOUR PLANTS if they are you need to lower the screen. what the screen will allow you to do is stop vertical growth and you can throw in some technical scrog stuff by shoving ALL of the leaves and stems under neath the screen and positioning the plants so ONLY THE BUDS ARE ABOVE THE SCREEN. this allows the buds to receive almost 360 degrees of light, which results in larger more compact buds. You need the screen to keep vertical growth under control! and repositioning the buds is just a little trick to increase your yield. I would stick to 12 plants. I know that about 1-2 weeks before your harvest your buds are gonna like that light so much that they will prolly grow a lot so use some twine (OR SOMETHING THAT DOES NOT ABSORB MOISTURE. STRING IS NOT SO GOOD) to GENTLY OH SO GENTLY bend them so they dont SNAP (cause they will) or BURN and so light can hit their lower areas (THIS IS CALLED LST ) funny how that works out.

doing all of that will help you maximize your space. All SCROG is, is using the screen at the very beginning. you are capturing the plants vertical growth and displacing it horizontally. that way you never have to move your light and THE ENTIRE PLANT recieves light. THE CONS are that you need to veg a little longer so you can fill out the screen but you are maximazing the potential in every single bud site. see the picture.

i do not personally use this method currently only because I am impatient and am having to move soon (kinda hard to move a screen full of a live MJ plant with anyone catching on.

keep hitting me with questions! I learn more by helping

Thanks for the advice.