question on ballasts and cooling

doing a bit of research on hid growing, and i don't wana screw up buying something that's overpriced and inefficient. so first question, is a ballast necessary, what do they do? and next i have seen cool tubes, these work without hoods right? so which would be better a regular fan cooled hood, or a cool tube.
Thanks for your help, this site is an amazing resource because of everyone here, you all have taught me so much in just a few months! Happy Growing

cool tube..fan cooled..how its shaped allows upmost air flow through and over the bulb..and if u can release that heat outside of ur op ..ur golden......as for the ballast..you can buy a complete kit with the bulb..cool tube and ballast...youll need all 3 plus an exhaust fan with a cfm rating that corresponds with room size and bulb/light size

For HID's ballasts are needed. They limit the current to the bulb.

Hoods vs cooltubes, your choice. Both do the same thing. The tubes can be a bit more flexible in that they can be placed in more positions, including vertical for a stadium grow. (but you will want a reflector if horizontal)

I prefer non-grow room air into the hood/tube then out of the room (so no grow room air goes through the light) But thats me. I'd also go with atleast a 6inch duct (4inch is a bit restrictive)


I went with a hood, because the tube where I bought, the internal reflector circled 180 degrees of the tube. Didn't feel like 'fixing'
something brand-new.

HID bulbs with built-in ballasts are typically fairly low wattage... so an external ballast is almost always a requirement. They control current to the bulb. Also, for HPS, an igniter is required(which usually comes with HPS setups, or HPS ballasts). HPS bulbs do not work without them.

A MH ballast will not work for HPS bulbs. Both ballast types have conversion bulbs which are designed to run on a specific ballast type. So you can just buy one ballast. Also, some ballasts are switchable. This allows you to bypass the igniter for conventional MH bulbs, and to engage it for conventional HPS bulbs.

Cooling requirements depend on your grow room. I've seen some growers just hang the bulb with no fixture at all, though I'd not personally suggest this due to the remote possibility of a bulb explosion(quite rare under normal operating conditions, having it fully exposed like this... would likely increase the chances of this happening). Indeed, I suggest a fully enclosed enclosure/fixture utilizing shatter-proof glass.

Thanks, so cool tube, beats fan cooled hood? could u throw a website my way? Amazing grow room by the way, i would never be able to leave that room.

big bud balls, an tea tree oil, man u guys were quick! here i was only thinking that tile master cared, i tip my hat to you all. So i guess now im thinking switchable ballast and conventional bulbs, and again ne information on a good ballast web site, and maybe stupid question but does the bulb screw right into the socket on the ballast or does the socket cord plug into the ballast. i was a cfl man but now i want big results and have limited knowledge on the HID asspect. Thanks again!

It depends if your ballast is remote or not. Some have plug-in cords with an mogul socket on the end of it(this seems to be the preferred), others are integrated into the fixture/enclosure(which probably means you have to throw out the entire fixture when/if it fails).

If I was you... I'd do some research on magnetic/electronic/digital ballasts, and bulbs that work well with specific ballast types. I haven't grow with HID in nearly a decade.

Well thanks for the help, just read ur cfl is better then 400w HPS, very well done. the question i have about it is in the end which would use less electricity, buncha cfls or just one HPS?

It'd depend on the total wattage of each one.

CFLs aren't necessarily better than HPS(lumen for lumen, they definitely are; watt for watt, no; 'better coverage' with less watts, very likely). It's more of a demonstration on how to get the most out of them. Growing more plants with similar(or less) wattage, is the real idea. Why grow 1 when you could grow 4, or 8? So even if the HPS makes the few plants within it's optimal reach yield more.... Having a greater number(under similar total wattage) of plants yielding less individually can still trump it in total net yield.

In the end, comparisons of HID and fluoros have pretty much made me come to this conclusion: you get what you pay for. A lot of CFLs can grow awesome plants(but they're a hassle!). And you'll basically be paying the exact same per gram. My (thread's) suggestions are solely for personal grow/stash. People growing, maybe 16 plants, tops(heavy user?). Hopefully topping, training, and SOG'ing them -whatever. And always use reflectors(or surround lights with plants)!
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For flowering, I don't think HPS can be beat. It has proven itself for decades as an excellent(albeit unusual) source for fruiting plants. For vegetative growth, I don't think fluoros can be beat(especially on the smaller scales of personals). Not CFLs exactly, there are higher efficiency and longer-life tubes(like VHO T5s, that's very high output). There are also fluoros designed specifically for producing photosynthetic-tuned(PAR) light and they grow plants exceptionally. Twice as effective as anything else being sold today(lumen for lumen, not watt for watt).

That's the thing about HPS. It has about 40-200% more lumens per watt than a fluoro, so this PAR difference is not so great in practice, and can be completely negated, and definitely turned around -most conventional fluoros fall under this last part. But, in the case of plant-specific VHO T5's, which produce about 70% of HPS's lumens per watt(both being 'top of the line' for their type, but readily available). They also more than double the plant-useful light per lumen! So that's around 140% as effective per watt. While on the lower end, 50% as many lumens, and about 10% better lumen for lumen... is about 55% as effective as HPS watt for watt. Probably: cheap bulbs could go lower than this, even!

Tube(T8 or smaller) fluoros pretty much have replaced HID in most buildings(rooms under 12' tall, largely, but with high-end reflectors and newer fluoro tech this can be increased to over 20'), and have been directly competing with HID since, uh, the 80's. Most(well over 90%) greenhouses supplement with HPS, and it's by no means the primary or sole light source for vegetative growrth. Using HPS in conjunction with MH and/or fluoro lights will give you the best results for indoor growing under all conditions, the ratio is the key to this door. Of course there's always an exception, and that's for flowering, where the ratio is almost always heavily favoring HPS or sun light, about 2/3rds the total light.

haha wow man, u know ur shit! and i have toyed with the thought of a few cfls mingling around under my hid, this will produce a wider variety of light, and will increase yield? as for ratio is there a magic number per square foot of grow space that should be cfl/hid light based on spec and lumen output?

I don't think there are any magic numbers.... As bulbs diminish in intensity a great deal over their lifetime(several years). Most give a range that starts with a minimum, and doubles to a 'maximum', as most bulbs will diminish in intensity by about half over their full life.

Plants don't do as well with narrow light sources. They require a fairly broad spectrum to grow their best. And 400-700nm(classical PAR range of radiance) wavelengths aren't the only useful ones. UV(below 400nm) has been shown to increase flowering yield in many species of plants, including cannabis. And even a little bit of NIR(just barely over 700nm, perhaps to as much as 800-900nm) has also been demonstrated to aid flowering. HPS emits a negligible amount of UV light(plenty of IR!). MH and fluoros emit about 5-10% of their radiance as plant-useful UV(CMH having the most besides specialty UV lights). Also, plants use different wavelengths of light for different functions. Providing a full-sprectrum allows it to be fully functional, and growth will be optimal given the other various environmental conditions are properly addressed. This makes for the highest quality smoke.

You don't need fluoros at all. A combination of MH and HPS is perfect for flowering, and HPS can do it alone quite well. 1 part MH/fluoro, 2 parts HPS(watts) would be ideal for flowering.

Look on youtube. There are plenty examples of HPS grows, and a few that mix MH with HPS. The plants speak for themselves. Extremely healthy and the most dense shining buds... anyone could hope for.

Fluoros are great for side lighting and 'in canopy' lighting in some HID grow rooms as they can be much closer/more adjustable and get to those 'weak points' in a room's light coverage.

i have tried hanging cfl's under hps light and the results are not worth the time, a cfl looses light at a rapid rate as distance increases, so what happens is that you have these cfl's blocking light from the hps without throwing much of there own so its a real negative, i have had good results hanging t12 tubes along side the room where its dark or using them under the canopy where the hid cant penetrate, if you do something like this i suggest using warm white bulbs as the cool white tend to make the buds stretch

I obviously don't have as much experience with this as TeaTree, but I love the science part of it. Yes, cfls hanging vertically are very effective at getting light to the lower branches that the hid has a hard time penetrating. This will definately increase your yield on the bottom portion of your plants, therefore increasing your overall yield. Typically, 2,500 lumens per square foot for vegatative growth is effective, yet efficient. However, for best results, the lumen per square foot output during flowering can range from 8,000-10,000. For reference, the sun emits 10,000 lumens per square foot on a sunny day. Lumens per square foot is also know as foot candles. So if someone says 5,000 foot candles, they just mean 5,000 lumens in a one square foot area.

An important thing to remember when considering light is the inverse square law. Light intensity diminishes pretty rapidly as the source is moved farther away. The formula is pretty simple. It is 1/X squared. X is the distance from the plants to the light, you will then need to multiply this fraction times your total lumen output.

For example, say you have a 400w light that has a 36,000 lumen output rating that is 3 feet from the top of your plants. The equation would be as so:

1/3(squared)=1/9

1/9 x 36,000=4,000 lumens at the top of your plants.

This law is universal and can be used whenever your calculating lumens and footcandles.

for a first round/trail run. CFL's for the veg state and a 150W HPS can give good yeilds. (the CFLs are easy to deal with and this gives time to work out some of the HPS issues ie:heat)