[Sprink]

Hey guys

 

I'm gonna flip a grow in about 3 days and I'm using the following bulb:

 

Phillips Master Son-T PIA Plus, whatever that means. It's a flowering spectrum one anyway

 

I know that I can use it from the flip because I did last time, but it's likely to cause more stretching isn't it?

I assume so, because people say to use MH first 2 weeks, and this isn't a dual spec HPS either

 

What do you reckon? I can use LED first 2 weeks if it'll be better

 

Cheers

[MDS]

SON-T PIA Plus is a high output Sodium tube, it's in no way dual spec & frankly the so called ones that say they are are talking cobblers

 

The so called dual spec tubes only output a little more blue light... A standard tube puts out relatively little at the blue end, so even a 50% improvement of blue light is still bugger all in reality..

 

If I was you I'd use that LED light for the first two weeks as it's no doubt designed for vegging & it will stop the plant stretching..

 

Happy growing

[Sprink]

Cheers dude, that's what I thought

Yeah the LED is great for vegging, I just wanted to be lazy and use the 1 light throughout

 

Defo need to minimise stretch, so LED it is for now

[Sprink]

Well actually, I didn't know HPS put out so little blue, so that's a good point

Might invest in some MH bulbs for this purpose

[MDS]

I was always incredibly dubious about LEDs as I'm sure Mrs Willy will testify as we have known each other on forums for many years...

 

I use mixed lighting to veg, IE a metal halide & a sodium tube & quite frankly I'm planning on sticking with the same idea as I much prefer the way the plants grow & the speed of growth

 

You see an MH might put out a good bit of blue light but it doesn't really put out enough red light which promotes root & stem growth, but if you combine the two you get superb results..

 

I recently found a seller on eBay selling 100W blue LED chips at around £10 for 5 delivered! The chips have a peak light output at 460nm which is about bang on...

 

My intention is to use possibly one or two of those 100W chips to replace a 400W MH... I reckon they could do it simply because the light output is around one frequency & not spread all over like an MH wich has green output (useless), yellow & god knows what else...

 

I was always slagging LEDs off saying they could never be any good

 

Sometimes it's nice to eat a little humble pie

[Sprink]

Aye well LED isn't quite there yet, but maybe getting close.

White light COB ones seem to be the way forward right now, although I don't know much about that.

 

A guy on here called Revert is into all that jazz, the results look very impressive

 

 

[MDS]

White is a bit of a waste in all honesty, a plant will only use certain spectra...

 

You might find it interesting to look up the specs of an old type of fluorescent tube made by Sylvania called "Grolux".

 

That thing was designed to grow plants under & the main output was bang on the money at both the red end (650nm) & the blue end (420 - 460nm) with very little else..

 

It looked pink... The light it gave off was pink...

 

Yes it might be handy to have more whitish light so it's easier to see if the plant is healthy, but the plant doesn't use much else than blue & red light... In fact it can't even see green light at all, because it reflects it all - hense why plant leaves are green to our eyes

Edited by MDS, 22 June 2016 - 02:43 PM.

[Sprink]

Yeah I don't think that white light is ideal, just that the most efficient COB ones are only white right now as they're not specifically for horticulture use

 

As far as I know, those COBs will be in different colours at some point, but some are already getting great results with the whites.

 

I'm sure @revert knows what's up with that LED shiz. I'm just a caveman really

[Anonymiss]

White is a bit of a waste in all honesty, a plant will only use certain spectra...

 
Or so the conventional wisdom goes, at any rate, but I read some research recently (I'll find the links later, if I can) which seemed to show that at high levels of illumination additional green light is more beneficial than extra red.

It's long been known that plants use green wavelengths (the McCree curve), but the increase in efficiency seems to come from the fact that reds and blues are absorbed by the chloroplasts in the top layers of cells, which become saturated and unable to process any increase in photon flux, whereas the green wavelengths travel further ("bounce around"), reaching deeper and unsaturated chloroplasts.

[MDS]

Yeah I don't think that white light is ideal, just that the most efficient COB ones are only white right now as they're not specifically for horticulture use

 

As far as I know, those COBs will be in different colours at some point, but some are already getting great results with the whites.

 

I'm sure @revert knows what's up with that LED shiz. I'm just a caveman really

 

What you have to remember is the light output is quoted in either lumens or candelas...

 

A plant doesn't know diddly squat about that... White is most efficient because it generates the most lumens per watt for what we see... Our eyes are most efficient in the orange spectrum, you might remember the old style SOX (low pressure sodium) streetlights that were around years ago that were just a yellowy orange colour so while you could see with it you couldn't see colours..

 

If you had a say two 100W White LED chips & 1 blue 100W & 1 red 100W chip I know very well what the plant would love even though it might be dimmer using the red & blue to your eyes...

 

We aren't plants...