lighting overkill

[Tom]

Not arguing, I'm just an obsessive-compulsive for detail

Not technically HPS/MH Tom, the Son-T's are still essentially HPS lamps

I’m a seat of the pants grower, I don't give a stuff about "technically", I don't care whether the blue is true MH or not, I have however been around mj sites for a fair while now and know what the growers are getting their best yields with, if you want details try google or the manufacturers sites (Philips is a prick to navigate), it's been a long hard day and I'm too wasted at the moment.

 

[Luke Skywalker]

I think they were pointing out that a son-t agro or plus, or a lucagrow is not an HPS/MH combination, it's just a particular brand of horticultural HPS with more blue spectra as opposed to non-horticultural HPS lamps.

 

I agree with elkel, it's possible to use 2x600w hps lamps in there, but not easy to manage. A single 600 or a pair of 400w lamps, one MH and one HPS on a rotary light mover would do wonders IMHO.

 

HPS and MH are two distinct types of High Intensity Discharge lamps, although both are perfectly good for growing plants under. HPS lamps are weighted further towards the yellow/red part of the spectrum, and MH lamps are weighted towards the blue. HPS watt for watt produce more lumens, but this doesn't necessarily translate into PAR watts, which are a different way of measuring light. Plants don't see lumens like we do, thus the talk about blue and red lamps. So a 400w HPS may put out more lumens than a 400w MH, but they may have similar PAR watt ratings, in which case they are giving similar amounts of usable light to the plants.

 

Most growers nowadays, (in WA at least) are growing with majority HPS lamps, particularly in single or double lamp setups. If you're going for larger grows however, it's definitely advisable to consider a mixture of HPS and MH lamps.

 

Another way of creating a more evenly weighted spectrum in blue and red, without buying more HID's, is utilising high powered compact fluoros, like Spectrums. These can be used as side, or in between lighting, and are available in 2600, 6400 and 14000k ratings, with 130w power use. I'm yet to find a PAR rating for these, but from the people I've talked to, and my own experience with one 14000k lamp for growing orchids, I'd say it's a definite option for a small room with heat problems.

 

A question for Jaikai. What are the types of fans you're using for ventilation, (centrifugal or axial-in-line) and what kind of airflow do they acheive... If you can vent the volume of the room or more in under 30 seconds then you'll have great heat control. Well, to ambient temp anyway.

 

So yeah, I'd say if you've got a 600w HPS now, just stick with that and you'll be happy with yeilds all else being equal. A light mover is a good idea, it would allow maximum utilisation of your space. Add about 4 130w spectrums in 6400 and 14000k around the edges of the canopy and you'll get excellent yeilds without the extra heat of a second lamp.

 

Hope that rant helps.

[Luke Skywalker]

Oh yeah, and the UV thing is not the main cause of thc production, although this can enhance thc content slightly. HID lamps shouldn't be giving off that much UV anyway, as the lamp jackets are a barrier to this. Some growers have experimented with using UV lamps, but I feel that their case for including dedicated UV lamps is unproven.

[jaikai]

hi all... just a tinkerer at heart and i got a lot of lights. just so you know, im not new to artificial lighting, wanted a few thoughts on this idea. give the whole thing up last night aftre watching the temp guages...prolly keep 2 ballasts on the roof and 1 cord to run 400 then swap to 600 hps at flowering...it is only a small room. i did have a much larger area with 1000mh but since reclaimed some of my shed for other pursuits (read: lost of car bits). so the twin 6`s is a goner, just one at a time`ll do me.

 

Luke, good to hear from you mate...the current fans are just cheapies ATM but i can drop the temps quick with 1@ top and 1@ bottom on just one globe...

 

ill finish the new fence/gate in front of the shed and get back to it ay.....

 

JAIKAI

[Pure]

I prsonaly would sugest that if you wanna try out mh to use a conversion bulb , it's one of the great advantages to runnign a 600 your able to get them

 

 

as for that amount of room , and two 600 watt lights I pulled off my first grow in a smaller space with as much lighting , however I REALLY had to make up for the space with powerfull fans , that was also in winter though

 

so in these up comming months I wouldn't reccomend it if you need to cover more area try a light mover as sugested already

 

or fork out for some aircooled hoods

[Buddy]

Here's some (boring??) info I extracted relating to lighting from the dozen or so ebooks I have on growing MJ........ Enjoy :smoke

 

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What is color temperature of a bulb?

 

The color of a light source entails a complicated relationship of different factors, that are important in determining the right light source for your garden. The advantage of Metal Halide lamps is that they provide high-quality, crisp white light in a variety of different color temperatures that meet the needs of many different users.

 

Correlated Color Temperature(CCT)

 

The first factor in choosing a color of lamp is to determine whether you need a warm or cool light source. The CCT, expressed in Kelvin degrees, relates to actual thermal temperature. If you've ever seen a piece of metal being heated, you know that as the metal gets hotter, it's color changes. The CCT rating of HID and flourescent light sources indicate how warm or cool the light source is. For instance a lamp with a CCT of 2700 Kelvin is considered warm; with a CCT of 4200 Kelvin is considered neutral; and one of 6000 Kelvin is considered cool.

 

Spectral Energy Distribution

 

When you look at a light source, you perceive seeing a single color, but you are actually seeing thousands of hues. The combinations of different wavelengths of light make up the color we see. The relative intensity of the various wavelengths are used to determine a light source's Color Rendering Index(CRI).

 

Color Rendering Index(CRI)

 

The CRI is an indication of a lamps ability to show individual colors relative to a standard. This value is determined from a comparison of the lamp's spectral distribution compared to a black body at the same color temperature. Light sources, such as metal halide lamps, are rated with a CCT; however, CCT does not provide any information on the quality of the color. For this, a CRI is also necessary. In general, the higher the CRI rating of a lamp, the better the different colors will show.

 

5K - 7K Kelvin: Strong Blue Light Promotes bushy growth. Ideal for rapid growth phase of plants. Greatly enhances all-around plant growth when used with super high output, high pressure sodium or 3K warm metal halide lamps.

 

4. 2K - 4200 Kelvin: Cool white Flourescents Can be used as supplimental blue lighting when used with a 3K source.

 

4K - 4000 Kelvin: Neutral Metal Halide Best single source for plant growth, producing shorter, bushier growth than 3700 Kelvin and color rendition. Used in general plant lighting.

 

3. 7K - 3700 Kelvin: Softer Metal Halide(coated) This coated lamp is used in general plant lighting and for more rapid growth than 4000 Kelvin produces.

 

3K - 3200 Kelvin: Warm Metal Halide Highest photosynthetically active radiation (PAR) value of all HID lighting for all phases of plant growth. PAR watts account for the nutritional value of light and are a direct measure of the light energy available for photosythesis.

 

2. 7K - 2700 Kelvin: High Pressure Sodium Lamps Redder color mix, used for propagation, blooming, supplemental greenhouse lighting.