Lighting Types and Intensities

Lumen

A unit of measurement of the total flow of light which is emitted continually from a source. One lumen is equal to the flow of light which is emitted from a very small wax candle.
The common 40 Watt incandescent bulb emits some 400 lm (lumen). So the efficiency of that bulb is 400lm/40Watt= 10 lm/watt.

LUX

= lm/m2, the intensity of light which falls on a surface.

Colour Temperature

- measured in degrees Kelvin, the color of a light’s output in relationship to the degree of heat applied to produce the specified colour of light. Daylight is measured around 5000 degrees kelvin

If we direct all light from our 40 Watt lamp towards a floor area of 1 square meter the intensity of light on that area will be 400 lux, (400 lumen distributed over 1 square meter, 400/1 lm/m2 = 400 lux,) which is a little better than moonlight, but far away from the sunlight intensities we need for growing plants.

The sun gives some 50 000 lm/m2 = 50 000 lux at the earth surface on a clear summerday. See the table below.

The 40 Watt incandescent lamp is not only too weak for growing plants, it also has too little blue in its spectrum and is far too inefficient. Fluoroscent tubes and HPS and MH lamps are the better choices.

Cannabis needs 24 hours of strong light for the first 4-6 weeks of vegetative growth. Then it needs 2 months of 12/12 hours of strong light and very dark, to flower and ripen. If they get less than 30000 lux they will still grow vegetatively but slower. And they will flower less, if at all.

 

Light Requirements of “High Energy” Plants
1000 – 5000 lux Min. necessary for life
10000 – 15000 lux Min. necessary for consistent but sparse growth
20000 – 25000 lux Min. necessary for robust growth
25000 – 30000 lux Max. Efficiency for Sub Tropical varieties
25000 – 50000 lux Max. Efficiency for Equatorial varieties

 

Plants need 25000-50000 lux too grow fast.

90000 lux Max. Sunlight Intensity on Earth’s surface This is too much light, it is not good for the plant.

Plants subject to intensities at this level or greater are at risk of “solarization,” whereby photosynthesis is retarded. This can happen at noon on a clear Tropical summer day, especially at high altitudes.

140000 lux Sunlight above atmosphere (Solar Constant)


More advanced theory: Scientific, but has many answers about how and why.

Air Temperatures between 23C (70F) and 32C (90F) are ideal for growth; beyond 35C (95F) can adversely affect plants, retarding photosynthesis, and, in extreme cases, can cause leaf burn if a radiant heat source is nearby.

Calculating with lumen, lux and efficiency:

The cheapest and easiest solution to the beginner is to use fluoroscent tubes. The usual ones are 120 cm (48″) long, and give at best 4000 lumen.

*****Ed Note: If you care to get a light meter and measure the light from various distances to your flouros, you’ll see immediately that you will want to keep the lights as close to the top of your plants as possible. *****

Your grow room must have at least these dimensions: 140 cm high (these plants get big, 180 cm is better, 120 cm long (to accomodate for the tubes), and wide enough, let’s say 60cm (2 feet). The easiest is to build an extra wall, made of silver tarpaulin or wood. This wall is placed 60 cm from a real wall, to create a space of say 200*260*60cm for use as a greenhouse or rather two. Build the wall and divide the space up into two small rooms. Make some type of opening, so you can take care of your plants later. Put in ventilation and cover all inside surfaces with al-foil using a stapler. We want the light to bounce around in there until it finds a green leaf to do its work in. As much light as possible is needed for the growth of the plants. The ventilation consists of a 12Volt fan which pushes the warm air from the green house through a plastic tube which ends outside the house to let the warm moist and odors out. Instead of a fake wall you can disguise the green house as a very big bass speaker, stereo wall, tv-stand, cupboard or whatever.

Buy the fluoros in ready-made units or do it yourself like this:

Buy the bare necessities to put up fluoros, that is reactors, lighters, tube holders, lighter holders, wire.7mm, capacitors and connectors.

Most of these devices have pushcontacts, that means you don’t have to solder or screw much, just strip off the insulation from the cable and push it in.

Put up as many tubes as possible in the ceiling of the green house. You might be able to get 6 tubes into every green house half. Every green house has a floor area of 0.60m*1.30m=0.78m2 With 6*4000 lumen you get 24000lumen. Divide by 24000lm with 0.78m2 to get 31000 lux, which is good enough.

Use hanging mounts for the tubes, they are cheapest and easiest to use. They also make it easier to pack the tubes densely in the cieling or hanging at different levels, hanging only in the thin electric cables. If you manage to get 10 tubes into the top of the green house you get 40000lm/0.78m2= 51300 lux in there.

As another example, let’s take one of the most popular hps grow bulbs:

 

Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
53,000 430 123.3 2000 16k Philips, SON T AGRO

 

The Son-T-Agro gives out 53000 lumen. If we use a reflector to direct all of that light towards a floor area of 2 m2 we get a light intensity on that area of 53000 lumen/2 m2, which is 26500 lumen/m2 (=lux)

We can see in table 3 above that it fits in: “25000 – 30000 lux =Max. Efficiency for Sub Tropical varieties”.

We add some daylight fluoros, 6 fluoros a 4000 lumen=24000 lumen. Divide by floor area 2 m2 to get =12000lumen/m2=12000lux

Together the hps and the fluoros give 26500+12000=38500lux in the 2 m2 big grow room. see table 3: 25000 – 50000 lux Max. Efficiency for Equatorial varieties.

This combination will draw 430Watt+6*40Watt+100Watt in the ballast units, total =530+240=770Watt of electricity.

Our total efficiency is 53 000 + 24 000 lm divided with 770 Watt, which is 77 000 lumen /770 Watt = 100 lm/Watt

At 38500 lux we have an illumination which is optimal for growth,

Illumination Chart

Light Intensity (lux) as a Function of Area Illuminated (m2)
Light Source lumens 1.0 m2 1.5 m2 2.0 m2 2.5 m2 3.0 m2 3.5 m2 4.0 m2
1000W HPS 140000 70000 56000 46700 40000 35000
600W HPS 90000 60000 45000 36000 30000 25700 22500
400W HPS 50000 50000 33300 25000 20000
250W HPS 29000 29000 19300
1000W MH 115000 57500 46000 38300 32900 28800
400W MH 40000 40000 26700 20000

For example, from this chart we can see that a 600W HPS used to illuminate an area of 2.5 m2 will result in a lighting intensity of 36000 lux. Note that this presumes that a reflector is being used so that all the light is being directed towards this 2.5 m2 area.


 

LIGHT BULB PRODUCT LIST

HPS Conversion
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
40,500 360 112.5 1900 24k Philips C150S63/RETROLUX
23,000 215 106.9 1900 24k Philips C215S65/RETROLUX
15,000 150 100 1900 24k Philips C260S64/RETROLUX

 

High Presssure Sodium (HPS) bulbs
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
140000 1000 140.0 2100 24000 Philips C1000S52 Ceramalux
130000 1000 130.0 2100 24000 Sylvania LU1000 Lumalux
130000 940 138.3 2100 24000 IwasakiEyeSunluxUltraAceMHcnv)
90000 600 150.0 2100 24000 Philips C600S106 Ceramalux
84000 600 140.0 2100 18000 Sylvania LU600 Planta
53000 430 123.3 2100 16000 Philips Son T Agro 430W
51500 430 119.8 2100 18000 Sylvania LU430 Planta
50000 400 125.0 2100 24000 Philips C400S51 Ceramalux
50000 400 125.0 2100 24000 Sylvania LU400 Lumalux
47500 360 131.9 2100 24000 Philips C360S51/EW Ceramalux
45000 360 125.0 2100 24000 IwasakiEyeSunluxUltraAceMHcnv)
29000 250 116.0 2100 24000 Sylvania LU250 Lumalux
28500 250 114.0 2100 24000 Philips C250S50 Ceramalux
27500 225 122.2 2100 24000 Philips C225S50/EW Ceramalux
22000 200 110.0 <2100 24000 Sylvania LU200 Lumalux
16000 150 106.7 <2100 24000 Sylvania LU150 Lumalux
6300 70 90.0 <2100 24000 Sylvania LU70 Lumalux

 

 

MasterColor (MH)
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
6200 70 88.6 3000 7500 Philips CDM70/U/M
6200 70 88.6 3000 7500 Philips CDM70/C/U/M
9500 100 95 3000 10k Philips CDM100/V/M
9200 100 92 3000 10k Philips CDM100/C/V/M

 

 

Metal Halide (MH) bulbs
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
125000 1000 125.0 4200 12000 Iwasaki MH BSX/BU 1000
115000 1000 115.0 4000 12000 Sylvania MS1000/BU SupMetalarc
115000 1000 115.0 3400 12000 Sylvania MS1000/C/BUSupMetalarc
111000 1000 125.0 3700 10000 Philips MH1000/U/BT37
40000 400 100.0 4300 20000 Philips MS400/HOR
40000 400 100.0 5000 20000 Philips 5K High Output Metal Halide
39000 400 97.5 4200 20000 Sylvania MS400/HOR SupMetalarc
38000 400 95.0 4200 20000 Iwasaki MH 400 Eye Sunlux
38000 400 95.0 3800 20000 SylvaniaMS400/C/HOR SupMetalarc
34500 400 86.3 3200 20000 Sylvania MS400/3K/HOR Super

 

 

Metalarc
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
23000 250 92.0 4300 10000 Philips MS250/HOR
23000 250 92.0 4200 10000 Sylvania MS250/HOR SupMetalarc
22000 250 88.0 3800 10000 Sylvania MS250/C/HORSuMetalarc
18000 250 72.0 3200 10000 Sylvania MS250/3K/HOR Super

 

 

Metalarc
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
15000 175 85.7 4300 10000 Philips MS175/HOR
15000 175 85.7 4200 7500 Sylvania MS175/HOR SupMetalarc
15000 175 85.7 3800 7500 Sylvania MS175/C/HORSMetalarc
15000 175 74.3 3200 7500 Sylvania MS175/3K/HOR Super

 

 

Metalarc
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
9300 100 93.0 4200 7500 Philips 4K Master Color ED-17
8500 100 85.0 3200 10000 Philips MS100/BU/BD/M/3K
7800 100 78.0 4300 10000 Philips MH100/U/ED28/HR
6800 100 68.0 4200 7500 Philips 4K Master Color PAR-38

 

 

Flourescent tubes, 48″
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
4400 60 73.3 3000 12000 Sylvania F48T12/D830/HODesigner
4250 60 70.8 4100 12000 Sylvania F48T12/D41/HO Designer
4250 60 70.8 3500 12000 Sylvania F48T12/D35/HO Designer
4250 60 70.8 4100 12000 Philips F48T12/SPEC41/HO
4250 60 70.8 3500 12000 Philips F48T12/SPEC35/HO
4250 60 70.8 3000 12000 Philips F48T12/SPEC30/HO
3700 40 92.5 5000 24000 Philips F40/AX50 Advantage X
3700 40 92.5 4100 24000 Philips F40/AX41 Advantage X
3700 40 92.5 3500 24000 Philips F40/AX35 Advantage X
3700 40 92.5 3000 24000 Philips F40/AX35 Advantage X
3600 40 90.0 5000 24000 Philips F40T12/ADV50/ALTO
3600 40 90.0 4100 24000 Philips F40T12/ADV41/ALTO
3600 40 90.0 3500 24000 Philips F40T12/ADV35/ALTO
3600 40 90.0 3000 24000 Philips F40T12/ADV30/ALTO
3500 40 87.5 4100 20000 GE Staybright
3500 40 87.5 3500 20000 GE Staybright
3500 40 87.5 3000 20000 GE Staybright
3400 60 56.6 6500 12000 Philips F48T12/D/HODaylight
3300 40 82.5 3000 20000 Philips F40T12HomeLightWarm
3300 40 82.5 4100 20000 Sylvania F40/D841 Desi800
3300 40 82.5 3500 20000 Sylvania F40/D835 Desi800
3300 40 82.5 3000 20000 Sylvania F40/D830 Desi800
3300 40 82.5 4100 20000 Philips F40/41U Ultralume
3300 40 82.5 3500 20000 Philips F40/35U Ultralume
3300 40 82.5 3000 20000 Philips F40/30U Ultralume
3280 40 82.0 5000 20000 Philips F40/50U Ultralume
3200 40 80.0 4100 20000 Philips F40T12HomeLightCool
3200 40 80.0 3500 20000 Philips F40T12HomeLightWarm
3000 40 75.0 6500 20000 Sylvania F40/D865 Design800
2325 40 58.1 6500 20000 Philips F40DXDaylightDeluxe
2250 40 56.3 5000 20000 GE F40/SUNSunshineFullSp
1900 40 47.5 3050 20000 GE F40PL/AQ/WS Plant&Aquarium
1875 40 46.9 3400 20000 Sylvania F40GRO/WS Gro-Lux
1600 40 40.0 na 20000 Philips Agro-Lite
800 40 20.0 6750 20000 GE F40PL Gro & Sho

 

 

Mercury Vapor bulbs
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
60500 1000 60.5 4300 24000 SylvaniaH36GW-1000/DXBrWhDlx
23000 400 57.5 3500 24000 SylvaniaH33GL-400/N Warmtone
22000 400 55.0 4300 24000 SylvaniaH33GL-400/DX BrWhDlx
13000 250 52.0 3500 24000 SylvaniaH37KC-250/N Warmtone
12500 250 50.0 4300 24000 SylvaniaH37KC-250/DX BrWhDlx
8900 175 50.9 <3500 24000 SylvaniaH39KC-175/N Warmtone
8400 175 48.0 <4300 24000 SylvaniaH39KC-175/DX BrWhDlx
4500 100 45.0 <3500 24000 SylvaniaH38JA-100/N Warmtone
4100 100 41.0 <4300 24000 SylvaniaH38JA-100/DX BrWhDlx

 

 

Tungsten Halogen Quartz double end lamps
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
22000 1000 22.0 <3200 2000 Sylvania 1000T3Q/CL
21000 1000 21.0 <3200 3000 Philips 1000T3Q/P/CL cl pl
11000 500 22.0 <3200 2000 Sylvania 500T3Q/CL
10500 500 21.0 <3200 3000 Philips500T3Q/P/CL ClPlusline
10000 350 28.6 3075 2000 GE Q350T3/CL/ULTRA
9200 400 23.0 <3200 2000 Philips 400T3Q/CL Clear
6000 300 20.0 <3200 3000 Philips300T3Q/P/CL ClPlusline

 

 

Standard Incandescent Bulbs 110V/230V
Lumen Watt lm/watt Kelvin Hours Manufacturer, Name
400 40 10.0 2000 1000 40 Watt Std. Incandescent Bulb

 

 


Equivalences:

1 lm/m2 (lumens per square meter)
= 1 lux (lx)
= 10-4 lm/cm2
= 10-4 phot (ph)
= 0.093 lm/ft2
= 0.093 foot-candles (fc)
1 meter = 3.3 feet
1 square meter = 10.8 square feet
1 foot = 0.3 meter
3 feet = 1 yard = 0.91 meter

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