Horticultural led's

Might I ask what sort of horticulture, legal or bootleg

 

at all, in a

All I can remember from reading up about this subject (in relation to fishtank illumination where I was trying to encourage plant growth) is that in general plants are green because they absorb all wavelengths apart from green, which they reflect. So, stay away from green LEDs and go for ones that emit red and blue for best efficiency of conversion of electricity to plant energy.

I remember looking at the emission spectrum for some of those high brightness floodlight type LED chips, and realising that some of them did not emit very much of their total energy at all, at a wavelength useable by the plant's photosynthetic machinery. so you have to choose wisely.

And use a decent power supply that can accurately control the current through the LED, otherwise you'll likely just blow the LED chip in short order

https://www.google.co.uk/search?q=p...UO8mDhQejxYD4Dw&ved=0CEcQsAQ&biw=1351&bih=715

 

Red, Orange and Blue LEDs. Ratio 7:1:1 is sometimes used. Standard 5mm HI clear lens types.
Adam

 

LEDs do vary their wavelength within each colour band so you may need to know the exact wavelength required. The exact power needed is difficult to work out because some plants require less light to grow. Having a quick look into it, plants need anywhere between 5800 and 46000 lumens per meter squared. So if you could find a bright LED which is 5800 lumens per watt, then you will need to supply 1Watt of power to give the required light levels or group lower power LEDs to do the same. 1 candela = 1 lumens if that helps.
have a look here for an idea of the LEDs you can get.

http://www.leds.co.uk/products/components/3mm_5mm_smd_leds

Adam

 

If you can find an LED that is 5800 lumens per Watt, don't buy it. The best ones available are in the range of 200 to 300 lumens per Watt.

Bob

 

Check out CREE. They make some very bright LEDs. The brightest LEDs are the white ones which you don't want. But you could group the lower lumen colour LEDs together to increase the coverage.

Adam

 

I'm curious... are LEDs being considered because they are perceived to be less expensive to operate than, say, full spectrum flourescents? Or is the main property the life span of the LED compared to other illumination types? Or is this experiment triggered by the government ban on incandescent that is leading all light bulb manufacturers to LEDs?

I ask mainly because it seems to me the more traditional illumination sources provide better light for the purpose than LEDs... better, at least, in the sense that they more closely approximate the light source plants really want.

 

LEDs are somewhat more efficient than fluorescents, but the main reason for using LEDs is that you can provide only the wavelengths needed by plants. Since plants appear green, this means that they are reflecting all the green light and absorbing the red and blue light. LED grow lights use only red and blue light, whereas a fluorescent, or even the sun for that matter, will peak in the green, which it totally wasted on growing of plants.

Bob

 

Welllll... as a general rule, yes. But with horticulture in particular, a little heat thrown off by the light source isn't necessarily a bad thing. Most plants I know about prefer a warm environment to a cold one.

 

If you check the NASA Websites, you will find a wealth of information on what wavelengths and ratios are best for growing plants.
They spent a lot of tax dollars researching this same subject.

 

Ahhh... you must not live in the frozen tundra like I do.

 

Plants can also benefit from orange light. The orange light helps with chlorophyll b.

http://www.ebay.co.uk/itm/like/2213...&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=95

Thanks
Adam