MedMan

While searching for light info I found this........



Plant Development is dependent on the specific spectrums of the light source and the usable light energy.
Only 37% of the energy in sunlight is within the wavelength (colors) useful for photosynthesis, while 62.4% is infrared (thermal energy) and the remaining 0.6% is ultraviolet. Photosynthesis in the plant leaf is powered by 1% of the sunlight that falls on the plant, 10% of the sunlight is reflected and 10% passes through the leaf. The leaf will retain 80% which is used for transpiration. Some of the light is re-radiated, while the fraction that remains is used for building building food from the carbon dioxide, minerals and water.


Usable Light Energy of Artificial Lighting compared to Sunlight.

Useable light energy for plant growth is measured in Micro-Einsteins ( micro-mols of photons per meter squared per second). The sunlight reaching our plant is approximately 2,200 micro-einsteins on a cloud-less day and 170 micro-einsteins on a very cloudy day.

For indoor growing under artificial lighting a range of 395 to 500 micro-einsteins is considered by experts at NASA to be minimal energy level for plant growth.

The higher the bulb wattage the further away the plant must be from the light source to prevent environmental heat stress that can cause the plant to transpire too quickly. Excessive transpiring can dehydrate plants leading to wilting and poor growth. Likewise, the further the plant is from the light source the less available useable energy is delivered to the plant. The indoor grower most tune light energy resources as well as other environmental variables for optiumal growing conditions.

Criteria for maximumizing the artificial light energy for photosynthesis

The indoor grower has several options for maximumizing the artificial light energy for photosynthesis, they are as follows:

Use light bulbs that have the highest level Micro-Einsteins per watt (reproducing natural sunlight conditions as much as possible)

Place the bulb as close to the plant as possible to deliver the highest level Micro-Einsteins per square inch (without over-heating the plant)

Filter out infra-red radiation (to use the only the portion of the light spectrum needed by the plant and to reduce heat build up inside of the plant cells)

Chart for Micro-Einsteins per watt of various types of light bulbs.

Here is a chart that can help you in determining the useable light energy for your plants. For optimum usable energy for photosynthesis, select a bulb that has the lowest wattage with the highest usable energy coefficient.

Bulb Comparisons (1)BULB Type: (2)Distance: (3)Micro-Einsteins: (4)Usable Energy Coeffecient

(micro-einsteins per watt)
(1) (2) (3) (4)
Incandescent
100 watt 3 inches 310 3.100
Incandescent
100 watt 6 inches 190 1.900
Incandescent
100 watt 12 inches 65 0.650
Incandescent
100 watt 18 inches 27 0.270
Incandescent
100 watt 24 inches 18 0.180
Incandescent
100 watt 36 inches 9 0.090
Halogen
20 watt 3 inches 1279 63.950
Halogen
20 watt 6 inches 413 20.650
Halogen
20 watt 12 inches 145 7.250
Halogen
20 watt 18 inches 122 6.100
Halogen
20 watt 24 inches 65 3.250
Halogen
20 watt 36 inches 32 1.600
Sodium
250 watt 3 inches 250 1.000
Sodium
250 watt 6 inches 99 0.396
Sodium
250 watt 12 inches 30 0.120
Sodium
250 watt 18 inches 14 0.056
Sodium
250 watt 24 inches 10 0.040
Sodium
250 watt 36 inches 7 0.028
Gro-Lite
100 watt 3 inches 420 8.400
Gro-Lite
100 watt 6 inches 135 2.700
Gro-Lite
100 watt 12 inches 60 1.200
Gro-Lite
100 watt 18 inches 31 0.620
Gro-Lite
100 watt 24 inches 18 0.360
Gro-Lite
100 watt 36 inches 9 0.180
Fluorescent
40 watt 3 inches 52 1.300
Fluorescent
40 watt 6 inches 36 0.900
Fluorescent
40 watt 12 inches 13 0.325
Fluorescent
40 watt 18 inches 7 0.175
Fluorescent
40 watt 24 inches 5 0.125
Fluorescent
40 watt 36 inches 2.5 0.063

For more info-http://www.aeroponic.com/aero65.htm

What there saying is a 20 watt Halogen this type=(http://www.aeroponic.com/aero6c.htm#High-Efficiency%20Lighting) produces more usable light than a 250w hps.

Has anyone actualy used this kind of light???
Any feed back would be appreciated.

Thanks in advance. MedMan

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If your soil is healthy then so are your plants.

TonDerudesKa

There is all kinds of info out there about how halogen is not a good light to use for growing. The sources are too numerous to list.
And....I have no idea what micro-einsteins are. I do know that if you put a plant under 20 watt halogen and one under a 250 watt HPS....there would be no comarison. The HPS would produce magnitudes better smoke. Your figures are interesting tho.......must take time to look at them a little harder

BTW, your link doesn't work

Thanks for the info
cy

MedMan

As im new to the internet I was unsure of the method for inserting an active link, but if you highlight the link and copy it to the address bar it works.

From this I found out that usable light for plants is measured in Micro-Einsteins.

I think that beacause the 20w quartz halogen can be placed closer to the plant (3inches) than the hps it provides 64 times more Micro-Einsteins (Plant Light)per watt to the plant.

Using the links have a look and tell me what you think.

Cheers. MedMan

__________________
If your soil is healthy then so are your plants.

bgetting

I would agree with CY, that the halogen is not a good grow light. I can't imagine putting a halogen 3 inches from any plant. Far as I know, though the spectrum of a halogen can support photosynthesis, it doesn't grow healthy plants. I'm am also confused by that table, I would like to know their source of data.

MedMan

BG, if you use the links you will hopefully understand.
Then give me your opinion.

Cheers. MedMan

__________________
If your soil is healthy then so are your plants.

bgetting

yeah, I checked them out, and they are not sourced, or anything. It's just that they leave out a lot of info, and what they claim is opposite to what I learned in school, and from professors that I worked for. I don't want to rain on the parade, I just don't buy it. sorry.
If it was tru then why aren't we all using Halogens? I find it hard to believe that the world has been misled on this for so long. Also, the site is trying to sell halogens, so isn't that convienent.
What are your opinons on it MedMan? Do you currently use a halogen? How have you found that it works?

MedMan

Sure,

Whilst NASA were experimenting to find the best Hydroponic setup (bio-serve program) they discoverd that 20w low volt quartz halogens provided the most effective light.

The bioserve program is a NASA project that will one day allow us to perpetually propagate plants in outer space. Its partly based on the university of colorado campus grounds.

I agree that a 500w Halogen is better for heating but with these 20w Halogens heat is no longer an issue.

There are MANY aspects of their research that have practical implications for marijuana growers. When it comes to lighting for plant growth for example, NASA has discovered
that halogen lighting produces more "usable light" for plants per watt than any other lights currently being made.

One of these lights would be unpractical for MJ but more would be perfect.

2moro im buying 20 of the 20w rated halogens and hopefully a digicam.

If you explore the aero link there is a (Realplayer) NASA plant lab tour.

Has anyone actualy used these 20w halogens??????


Cheers. MedMan

__________________
If your soil is healthy then so are your plants.

bgetting

I'd still like to see the emmision spectrum. Also, there are issues with growing plants in space, and I am curious whether this means optimal for space growth, earth growth, or both. Let me know how those 20Watters work. Good luck.

MedMan

You can use the lights any where, optimal conditions do not change and as for how they work ill let you know.

This will be a very interesting experiment, any other views or info from using the 20w halogen would be appreciated.

Cheers. MedMan

__________________
If your soil is healthy then so are your plants.

lilbuddie

Well If I am reading this correctly it is saying a 100w Incandescent buld provides more usable energy than a 250w HPS????????

Am I reading this right??? I find that strange since that it has been scientifically proven that HPS are some of the most energy efficient bulbs around much more so than incandescents.

One other thing they only focus on is the veg part of growth but leave out flowering .. which to us IS the most important part of the plant and even suggest filtering out the infrared spectrum as well ...again ... huh? How does that help a plant needing to produce flowers?

Like I always say what the heck do I know, I'm just a poor dirt farmer

LB

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