Uncle Ben/borntokillspam,

First off, I want to express my gratitude for the wealth of info you have provided in your threads. You are my go-to-guys as I try to soak up as much wisdom/proven techniques as possible.
This will be rather lengthy, sorry 'bout that, guess that's one of the "perks" of being the resident gurus! I have tried to limit my questions to topics I have not seen you cover in threads.
My set-up consists of the following;
Grow room - appx 4x8x8, soon to be painted with Behr's Ultra White
Light wattage - TBD... I plan on growing only one large plant at a time (compromise with the wife), so I don't know how much sq footage footprint the canopy will eventually occupy, but I want to take advantage of the space and grow big. I would like to concentrate on mostly sativa strains. I will be using Ben's 4 cola method of topping. 1st question - The cost of the 600w and 1000w set-ups is pretty close (beside electricity). Ben, you have previously stated that you prefer to grow under 15 - 25 watts psf, 600 falls at about 19wpsf, 1000 at about 31wpsf. With growing a larger plant, would the larger bulb be beneficial in penetrating deeper through the foliage layers (want to keep those leaves happy), or just overkill/detrimental? I will be using an Easy Cool reflector, so heat should not be a factor. Ideally, how far should the lights be kept from the plant?
Ventilation will be provided by a dedicated ac duct (don't know why one was put in a closet, but it works) for in-flow, a Grow-Bright 4" in-line fan and charcoal filter will provide exhaust for the lamp into unused attic space. One wall mounted oscillating fan will provide additional circulation. Question(s) - What is your opinion of the ideal indoor day and night temps for sativa/mostly sativa strains? Does this change between veg and flowering stages? Does this differ from indica/mostly indica strains? Have you noticed any difference in fans blowing directly on plants as opposed to not?
Humidity control - TBD. I would like to know your opinion of ideal humidity % for sativas in the flowering and veg stages, this will help determine the need for humidifier/dehumidifier. How does this compare to moisture percentages for indicas?
Soil - this is the big one for me... I plan on using about a 15-20 gallon Rubbermaid storage container with drainage holes to grow the plant. In a container this size, I'm hoping that root "spin" will not become an issue. I want a super strong root system. Since I am growing one plant, and I can do germinating and vegging in one room, is there any benefit to germinating and establishing in a smaller container, and then upcanning? For the soil itself, Ben, I have seen that you mix your own soil, do you have a recipe? Also, any grow journals that could act as a loose guide for feeding frequencies?
I know this is asking a lot, but I have done quite a bit of research to get a good base, and feel like these few things will have me prepared to complete a successful grow.
Thanks so much!

Ok, Buuuump.

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"I'm a grower, not a show'er"

There is benefit to working up from smaller pots.. Especially if those pots are coated with a copper paint product.. There was a thread on it in this forum not long ago, and Uncle Ben posted some good comparison pics there regarding root density.. Don't be chincy when drilling your drainage holes, make alot, and make them big..
What are your ambient humidity/temps in the space?? Textbook speaking, ideal humidity will depend on the temperature, CO2, and how much light is hitting the plants.. Sativas are more less likely to fall victim to mold if the humidity is too high, but generally 55%RH is the typical target, and measures are only necessary in fairly extreme situations..
Amount of light the plant can use also depends on CO2, but they can definately use more than 20W/sqft for 12hrs.. When the sun is directly overhead it can cast up to 140W/sqft, but its not overhead all day.. While buds that caught ~20W/sqft might be the choiciest nugs, aiming for that is going to devastate yield.. Regardless, you'll have a spectrum of intensities.. When we say Watts/sqft, we're just talking averages.. You could download software to map oout intensity across an area for a given height if you're curious.. I like to aim for 40-50W/sqft, and I had no problem parting with the beefiest buds that sat right under the 400's..
The area itself isn't suited for a single light without a mover, but that won't be a problem because I can't imagine actually filling it with one plant.. M Blaze grows giant sativas indoors, I was a small stout plant guy myself.. And a multiple 400W guy too, so I really don't have experience with 600-1ks..
Temps, I'd aim for 80ish/65-70ish, but the way it usually works is you find out what temperature your setup runs at, and if it seems to work you just consider yourself lucky you don't need a bigger fan and declare that your target.. Look at the sativa leaf though.. Usually plants that need to cope with heat, water loss, and too much sun grow thinner leaves.. DJ short swears by growing strains in conditions similar to where they evolved.. Mimicking solar movement and all..
Your fan is going to need to be big enough to maintain negative pressure too.. With forced air-conditioning, you'll face odour leak if it isn't.. I don't know if AC is needed for that grow in 256cuft.. Passive intake may be enough.. You can play around with a bunch of incandescents to test out the area for heating/cooling..

Thanks for taking the time to respond, greatly appreciated!
The larger side of the closet (door is nearly centered) has a space of roughly 3.5' x 4' or 14skiff. I believe that this will be the area utilized for active growing. I listed the total sq footage available on the odd chance I did produce an MBlaze type plant. I don't think that's likely.
I've decided my light set-up will be (1) 400w and (1) 250w run simultaneously, that will put me at about 46.5 wpsf, right in the middle of your target range (the 250w happened to be available from a friend, otherwise I would probably have gone with a 600w). I want to use both MH and HPS for increased spectrum, I will use the 250w to power the typically off-cycle bulb (ie. MH during flowering).
I decided to move up to a 6" exhaust. The a/c system does not have to be utilized, it just happens to already be present in the closet. Also, it is smaller than your typical living area feed, so the airflow will be less. I would like to use it to increase the air circulation since I am not utilizing CO2. I keep the house at about 75 during the warmer months, and can't sleep if it is warmer than 67 at night. Generally that closet is about 3 degrees warmer than the living space, so that should keep me between 70 and 78 degrees.
The pot I would like to use is a larger storage container (appx 18" deep x 1.5' x 3') lined with a spin out treated material that comes in 3'x3' sheets. I really want my roots to have the ability to grow as big and healthy as possible, because I am planning on keeping the plant in veg for 6 weeks.
Thanks again for the help! Anyone else who sees something I should consider, please feel free to post!

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"I'm a grower, not a show'er"

You'll get more contact with that spin-out if you work up from smaller pots lined with it..

Ok, I'll take that into consideration, thank you.

__________________
"I'm a grower, not a show'er"

Yea, you want that root division to start early so that the mass is dense throughout the whole rubbermaid, not just a dense perimeter at the edges of the final planter..

One gallon to five to finish, or start out smaller?

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"I'm a grower, not a show'er"

Not having read BTKS response, here goes....

FWIW, I do SOB (my way of saying Sea of Bush). Less but bigger plants means less hassles.

You can grow a huge plant with only a 250W HPS, I've done it. Understand that it's the total light received by the plant that's important, not necessarily the watts. Watts/s.f. doesn't mean squat in the real world. To achieve such efficiency (you're buying light, not watts) I use movable side reflecting panels keeping them close to the plants at all times, paint the floor (plastic) white, use a very efficient, SMALL, horizontal hood with a gull wing specular reflector, etc.

Time to buy a light meter that registers to 10K f.c. Failing that, close enough to keep the leaves a medium green.

90F/65F is fine.

Try to keep it a bit cooler during flowering. THC ramps up a bit with cooler temps and lower RH during flowering according to studies done on the issue.

1. Not really.

2. Only difference is less fungi pressures. Having a fan on your plants to strengthen stems is yet another forum myth.

You're splitting hairs now. Keep the RH lower for indicas due to fungi pressures. Your root system is supposed to supply adequate moisture for the plant.

Start in a 20 oz styro cup or 1 gallon pot, upcan to a 3-5 gallon pot, sex and finish. Unless you have the headroom for a huge plant and can manage your watering schedule to a T, a 20 gallon Rubbermaid is just asking for trouble.

Plants are dynamic. IOW, charts and such suck. Learn to read your plants, not some chart designed to confuse so that you'll buy more products. Plants like small does of salts, reason why organics like blood and bone meal are so good. Nothing wrong with a balanced Osmocote food too.

My soil recipe archive:
Here's the Spin-Out thread: Spin-Out for chemical root pruning

Good luck,
UB

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PLANT MOISTURE STRESS aka leaf edge/tip curling - symptoms and solutions
Note- Due to some technicality, I can not reply to "New visitor messages"

Great stuff!
You guys did not disappoint! Thanks again to both for taking the time to help me with these questions. +REP to both.
I hope to be set-up for start by the end of the month, I will check in soon!

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"I'm a grower, not a show'er"