What kind if yield would I get from a set up like this (is it overkill)

Just start growing, work on 'not messing up,' and don't consume yourself with stuff like this. 
 
When I started growing I sucked bc I had too much pride to ask for help and was overly concerned w/ what my yields would be. My first harvest wasn't that great but some plants w/ strong genes turned out alright. 2nd harvest went poorly - I nutrient burned several plants, and only a couple were worth smoking. Then I started asking my GC friends in the hobby for help, and by my 3rd harvest I was growing some of the danker bud I had ever smoked bc I focused on perfecting my growing skills instead of worrying about how many grams I'd wind up with. 
 
Focus on quality - doing your feedings right/on time, and keeping up the ideal conditions/maintenance in your room. Bc I can tell you - I've harvested a pound of weed that sucked, and it's straight up depressing filling your jars w/ subpar marijuana. 
 
To throw some numbers your way though - I had a really ghetto grow room when I started, and one of my better harvests in a 6.5ft x 6.5ft x 6.5ft tent was 24 ounces with 2, 600w lights. Critical Mass from Mr. Nice was the strain. 

 

Weight(dry weight) is based on light output.  The general rule of thumb is you get half a gram per watt of light, every 30 days of flowering. The actual equation is this (.5 x w/30),  so if you have a 1000w light,  you should be yielding 500g every month(on a perpetual garden, x2 if you are growing from seed on a 60day cycle).  If youre not getting somewhere close to that(close because different strains will yield different),  something is wrong.  
 
 
Now,  this benchmark is for a seasoned grower.  Could a person expect to yield these results on there first couple of grows?  Doubtful, but even 1g per watt is achievable with some strains.  I read books up the wazoo, 5 different (which is what i would recommend for you if you havent read 1 already, Indoor Marijuana Horticulture by Jorge Cervantes is 1 of my favorites and 1 i still reference even to this day) before i even tried my first grow and i yielded about half the benchmark.  Still plenty of kinks to work out in new setups but once you get it going you work your way towards the benchmark through every new crop.  Hope this helps and good luck!!!

 

You'll be fine with that set up I'd try 4-6 plants before 8

 

MrThoughtCrime said it pretty well, if you're a first-timer.

If my conversions are right, that's a normal 4' by 4' by 6' tent, yes?

If so, 1600 watts IS "overkill", but all it means is watch your heat, and pay attention to your plants for leaf burn....and make certain if you do get burn, it's lights, not nitrogen poisoning from overfeeding, or nutrient deficiency, before correcting. Like he said...concentrate on quality...test, test, test. And plants like a routine...feed them at the same time, the same number of days apart, same with application of antifungals. Most people run 400 to 600 watts in a 4 by 4, though I know a few (very good) growers who run 1000. But even 1000 leaves you with far less light intensity than sunlight, so your yield is lower and less potent than outdoors grown in the right place/conditions.

What are you doing about mites? This may or may not be another "give the plants a stable routine".


DO NOT run 8 plants in a 4 by 4, unless you want them crowded and stunted. Even small plants that reach sexual maturity (able to flower) want a minimum of 18 inches by 18 inches each, and you need room to be able to turn them, and move them around a bit. Even 4 plants in that small an area is a bit much, but doable with minimal crowding. If you plan to use the whole 6' of headroom, knock off a foot for your light hanger, as you won't get it to hang right against the ceiling (might get the HOOD there, but the bulb is 4 inches lower, about 2 inches diameter, so the bottom of the bulb is 5 inches below the ceiling, then you need the 18+ inches of space between lights and plants, so you have to calculate height when flowered for the plant to double its height during flowering WITHOUT getting higher than about 4 feet off the ground....which means you'll have to flower it at about 30 inches).

That's going to drop yield DESPITE having that much light. But that's what my own indoor grows were like, this last three crops, and I got relatively low yields (ounce to ounce and a half per plant), but such high quality in taste and potency that what I brought to my dispensary never made it to the shelf...the manager immediately purchased it for his own use. And I grew under far less light than you're using (400 effective watts LED, 40 watts UV reptile bulbs, and 200 watts CFL), so I could have done better. Dunno if it would have upped quantity (doubt it, just wasn't room), but it almost definitely would have increased quality even more.


The "gram per watt" rule is horseshit, even with full sized plants. As a rule of thumb, it often comes close, with experienced growers...but they know how and where to spread the light, know when to shift and turn the plants, etcetera. The truth on that is only plants in the direct, not peripheral, footprints come anywhere near that. Pretty simple to understand why...only the plants getting direct, straight from the source light are actually getting the light intensity the source is rated at. Anything else is reflected light, which loses energy, and becomes more diffuse (or gets magnified into a hot spot, and the wavelengths get changed through mutual interference), or loses intensity as outside leaves are shaded by the mass of the plant they have to pass through (penetration issues don't just come into play on the vertical--though with 1600 watts, I don't expect that's an issue for you...lol).

If you're going with dwarfed plants...you'll get a LOT of good sugar and water leaves when you flower...more than you will in weight of dried flower (last crop I got a pound and a half, wet, which converted, when processed, into 2 gallons of cannamilk rated at 25 mics to the cup, and 2 pounds of butter that...well, I used a quarter pound stick to make 2 pounds of buttermints, and THOSE tested at 32 mics to the gram). And it can be used right off the plant, no need to dry. GREAT opportunity to make cannabutter, cannamilk, hash, or oils. Don't pass it up, and don't limit yourself to "convention", making cookies and brownies...send me a PM, I'll give you a few recipes I use that fly out the door at my dispensary, every time I bring them in.