Again a learning question for me
I will soon have to replace the bulbs I'm using. Please excuse my dumbness but am I correct in assuming that using a 600watter instead of a 400 may increase the fatness and density of buds?
Or do you use a bigger bulb when you have more space to play with?

Ms Powerband

How many watts per square foot do you have now? I don't think theres any point in going above 80W/sq ft myself but others may differ.

I belive that 600w lamps are the most efficient in regards to lumens per square foot or per watt (?) but they are alot hotter, plus you will need to get a 600w ballast as they wont run on a 400w one.

I think...

I'd reckon the area Im playing with is approx 1m square with 400watt bulbs at the moment.

Ms Powerband

No on second thoughts its about 1.25 m x 1m

just changed from a 600 from a 400 ... differnce is defo noticable

not too much more heat either imo 5-10c at the most

So what difference have you noticed Lawless?

Ms Powerband

either or both I would have thought ....

Lately I've been musing on the relative merits of lower-powered lights that can be used closer to the plants - versus big lights that have to be kept further away from the growing tips.

The key reason I plan to treat myself to a digital 600 watt lamp for my new 10 square foot "room" is the higher efficiency compared to my two 250 watt lamps which now probably have their own permanent home.

Maximum efficiency is usually achieved by a lowish watts per square foot and small buds - SCROG and the like - which would be the same choice if you were using fluorescents.

...although it would also allow you to grow a single plant for that "High Times centrefold" effect

Replacing 400w with 600w also requires a change of ballast, which may prove expensive.

Yes you should get a better yield, and yes, the size of the room may prevent a larger bulb being used.

There are also choices to be made in the area of reflectors, some really do give increased harvest. I changed from "budget" to "dimpled de-luxe" and saw a good result.

Also moving up to 600w, may result in having to increase the size of ventilation fans.

If you can get that 600 in and can control the temps then you go for it

The difference in growth from a 4 to a 6 is very very noticable

Owd

600W lamps are the "sweet spot" in terms of efficiency but I reckon there's more people running 600W lamps that should be running 400W than vice versa. Lamp efficiency only matters once you have everything else dialed in - sod all point in 600W of light when you don't know how to deal with it. When I switched to 600W a couple of years ago (all boxed up now) I don't think I ever managed to use even 80% of the lamps output. After a while I recognised that 400W (250W now) is less than 600W regardless of efficiency and costs less

Dunno whether that's helpful or not really

a square meter CAN be used in your space, but what kind of strain are you planning to do ... some strains will just not perform any better in your "box".
you'd need serious extraction.

t "upgrade"get a timer, and two UV tubes from the pet shop.
install timer on 2 x 20 or 1 x 40 minutes a day..
they will seriously affect the potency without heat issues,.

simply place along the sides. on canopy level, and if yer really fancy . some more alongside the reflectorwings..

another upgrade would be getting a son-t bulb if you already havent got one.
master son t is good too , the more expensive , generally the better
all 400 w bulbs can be used in your set up
just make sure its hps and not metal halide/ mercury vapor /etc

i like using a 600 watt myself, but i only use half my growing room, since it produces a shiload of heat.
buds get fatter , but same potency as 400 watt....

Ive noticed the buds in the middle of the plant that woud normally be small-ish with a 400 get pulled up alot more & end up like mini main cola's

the buds are alot denser than before - the main buds are "rock hard" ... just genrally better/bigger buds

Not too much more heat either atm im running 26c & 49% Rh

Go for it ... its my 1st full grow using the 600 ( put it in half way through the last) & im very happy with it , it just seem more efficent than a 400

Is there much difference in how much electricity 600watts chew up as compared to 400 watts?

And thanx Yoda, growing W/Russian at the moment. Just thinking ahead regarding bulbs. Good job you reminded me about ballasts cos that was something I hadn't taken into account either
Not just the price of a bulb to think about

Ms Powerband

a 600w bulb will use a little more than 600 watts, probably about 660. a 400w bulb will use around 400-440w, but this will increase with time, and light output will decrease.

First thing is are you in an Economy 7 area where your electricity is discounted (usually) between 1 AM and 8 AM? If you are then forget about cost - I pay 3.9p/kWh at those times so an extra 200W is what? 10p a day at a rough guess?

If you aren't then you'll be paying around 9 - 12p/kWh depending on supplier. An extra 200W will make a noticeable impact on your electricity bill - its up to you to decide if the increase in weed is enough to cover that.

Now SirBob, you should know by now that what you have said makes no sense to me

I understand pounds and pence... But thanx anyway

Ms Powerband

in the end , its all about how much dope that closet brings to your stashbox.

the relative extra investment it takes, is very mch compesated for , by the much fatter buds.

2x 250 watt is usually less productive than a 400 watt
same goes for 2x400 wat > less than 600 watt


this is all because of the heat that is emitted by a single bulb / vs 2

white russian is a hybrid...depends all on our set up ..
i'd go for an aircooled 600 ..but still get an extra extraction fan , to be on the safe side of things.

box-grows beg for automatic watering btw...
i did several box grows without automatic watering .
densenst buds, but very poor yield,,,
( it was a 400 watt bulb on 3 square feet.. product was top quality..)

This is counter intuitive. There may be extra heat, but 2 x 250 watt HPS lamps should produce as many lumens as 1 x 400 and 2 x 400 watt HPS probably produce more lumens than 1 x 600 watts. Apart from the problam of disposing of a little more heat, the only other issue is cost.
I would guess that with some room proportions, 2 lamps will work better unless you really go to town with advanced training techniques.

In my present cupboard, it would have been almost impossible to achieve the same results with a single lamp....