lighting

[allhailthebud]

hey

 

does itmatter ifyou start off with a HID light or HPS light ?

 

which is better ? i can get a 400w HPS light and fitting for about $50

 

shouldi buy it, and use it as the main light?

 

also, if i had 2 150w HPS lights, woul;d i have them on 24/7 or 12/12 ?

 

let me know about the 400w HPS too,would i leave it on 12/12 ?

 

ta

[Luke Skywalker]

HID means High Intensity Discharge, a kind of lighting system. Which can be either MV, mercury vapour, not suitable for growing; MH, Metal Halide, suitable for vegetative or flowering, although not as many lumens per watt as a HPS lamp, and far more blue than red spectra emitted, making short, squat plants, usually used for veg stages or as a supplimental light to even out spectra in larger grows; and HPS, High Pressure Sodium, which can be used for veg and flowering, put out high lumens per watt and are usually fairly heavy in the red spectrum. There are also lamps made of both MH and HPS with altered spectrums, with more red in the case of the Sunmaster MH and more blue in the case of the Son-T-Agro and Plus HPS lamps.

 

All of these lamps consist of a shade/socket for the lamp, a ballast, which regulates and ignites the lamp, and a globe. The ballast has to be suited to the lamp type, so a 400w hps ballast won't work for a 400w MH lamp, as they have very different sequences to ignite them, and are fundamentally different. You can get conversion bulbs, which will work in other types of ballast of the same wattage, but there is a cost in lumens involved.

 

A $50 400w is likely not working IMHO, unless you're getting it off a mate who is really, really wanting to get rid of it. Even then, I'd insist on seeing the unit run before I bought it. A new one usually costs about 200 bucks, maybe a bit more or less depending on what brand and where you got it. You should also know that globes don't last terribly long, and if the globe is more than 12 months old you should likely get a new one anyway. These cost anywhere from 50-200 bucks, once again, depending on type, brand, and where you get it from. If you get a kit for that 200 bucks for a 400w you'll get all of these, shade/socket, ballast and globe, reducing your initial cost.

 

Once you pay for the initial cost though, it only gets cheaper.

 

As to the 12/12 or 24/7, (I assume you mean no dark period for that one), that's determined by the stage of growth of the plant. MJ is stimulated to flower by the length of the dark period it gets each night. If it's short, or the dark period is interrupted, then the plant will stay in a vegetative state, putting on more leaf and stem growth. This is replicating the long days/short nights of spring and summer, which in nature is when MJ germinates and grows.

 

When the plants are sexually mature indoors, which can be whenever you want for clones, or after about 6 weeks for seeds, (seedlings have to grow out for a certain amount of time before they'll yeild, and you have to remove males from the garden too) the light cycle is turned down to 12/12, with absolute darkness imperative for the 12 hours of darkness. This will then trigger the plants to flower, and will proceed to then double or even triple in size from the end of veg, first laying down the structure of the buds and then filling them out with flowers.

 

So grow under 18/6 or 24/0 for vegetative growth, then when the plants reach maturity and(/or in the case of clones) are @ 1/3-1/2 of the maximum finished height available, then turn down the light to 12/12 and keep the dark absolutely dark.

 

You'll need to keep the lamp a fair distance away from the top of the plants too, about 40cm for a 400w or so, a bit less if you have an air-cooled shade. Make sure you factor this, as well as your growing system, (water has to drain with gravity back to a res/waste catch under the plants, or out of the room altogether via a drain) into designs for a growroom. It can help to map it all out in a drawing.

 

You'll also need a good extraction fan, as HID lamps, whatever their type, put out most of their energy as heat, which has to be removed from the growroom. Ventilation also provides fresh air with co2 for the plants, which in an enclosed growing space can quickly be depleted by fast growing plants. A good measure is to get a fan (it should be a continuous rated fan, preferably centrifugal for maximum speed and pressure, although small axial fans, if of good quality, can be fine for small spaces) that can exhaust all of the air from the growing room within 5 minutes. If you can reduce this to every 1 minute or less, all the better. There is no such thing as too much ventilation, unless you live in a very, very cold area. The heat generated by HID lamps is substantial, and MJ grows like wildfire, consuming co2 all the time.

 

So yeah, I'd be wary of the $50 HPS set, I think it'll likely not work or be really old, in either case you'll probably end up spending more to fix it, or get a new lamp, or may be defective in some way. The money spent on a new one is far and away worth the value. A good hydro shop should offer layby too, so even the poorest of us can put aside a few bucks a week and pick up a cheap gull-wing 400w lamp. From there, you can only get better.

 

Oh yeah, and you could use a pair of 150w lamps, (you'd need the ballasts for both too) for the veg, and change over to a larger lamp in flowering, but usually most growers on a small scale will just use the same lamp for veg and flower. Son-t and added blue HPS lamps are fine for both veg and flower, and whilst it may not be the most efficient use of energy, the costs are minimal for running a 400w lamp even 24/0 so it's pretty much a waste of time unless you've already got the 150w units. You could use a 150w for a mother room though, but I'd add a few cool white fluoros with some more blue in them. The smaller wattage lamps usually don't have spectacular amounts of blue, which is important in the vegetative stage.

 

Hope that helps.