Squ1rrely
Member
This was a segment in the Volume 5 Issue 1 printing of SKUNK magazine.
by Ed Rosenthal
I found this interesting and thought u might too. these entries are verbatim.
CRITICAL LIGHT PERIOD
The 12/12 formula has been accepted without question by growers all over the world. Probably one of the reasons for this was my discussion of the technique in some of my early books. The 12/12 regimen was selected because my co-author an I reasoned that no matter what critical period a variety might have, given 12 hours of darkness it would flower. However most marijuana varieties need fewer than 12 hours of darkness to flower.
If marijuana plants grown outdoors required a 12-hour dark period to flower, they would not be induced to start flowering until September 21, the first day of autumn, when day and night are equal length. They would then ripen 6-8 weeks later. In real life most modern varieties ripen between early September and late October. Budding was triggered 6-8 weeks earlier. For instance, an eight-week variety that requires 55 days from forcing maturity, which would normally ripen on October 1, would start flowering August 1. At that date in San Francisco, sunrise occurs at 5:14 and sunset at 19:18, a total 14 hours and 4 minutes. Dawn and dusk add another 15 minutes of red light. Plants use the absence of this spectrum to measure the dark period. The total lit period came to about 14:20, leaving 9:40 minutes of darkness. The critical period for this plant was 9 hours and 40 minutes. If it was given just 10 hours of dark period daily indoors, rather than 12, it would still flower.
Gardeners growing outdoors who discover the critical time needed to induce flowering can use this information to get more efficient use of their indoor garden. Currently, plants grown under a 12-12 cycle spend half their time in the dark. if the plants have a critical flowering time of, for instance, 10 hours of darkness daily, they can be provided 14 rather than 12 hours of light each day so that they receive almost 17% more energy, which they use to produce sugars used for more and faster growth.
Manipulating Light Outdoors
Sometimes I think nature didnt get it right as far as marijuana ripening is concerned. If it were determined by human needs, the buds would be ready late spring so they'd be readily available in early summer, the party season. If they ripened at the best time for the farmer, it would be in high summer when the weather is warm and the sun strong. Alas, nature has chosen the fall. The harvest can be good if the weather doesn't attack first.
With a bit of effort you can manipulate the outdoor light cycle to grow and flower the plants at your convenience. I think that the best and most convenient time to harvest is during the summer rather than the fall. Buds that ripen midsummer experience much more intense light and much more UV spectrum than fall ripened buds. The intense light gives plants energy to grow bigger buds while the UV light increases their potency.
To force the plants to flower during the summer they need to receive the critical dark period each day. Covering the plants with a blackout cloth each day so they receive 12 hours of darkness pushes the plants into flowering mode. Decide whether you are going to restrict light at the beginning or end of each day. If you restrict light during the morning, place the blackout cloth over the plants just before dawn; then remove it promptly at the appointed time. For instance, if the sun sets at 8:30 PM the curtain, which was placed on the garden at 5:00 AM right before dawn, is removed at 8:30 AM (if you know the plants' critical time period for flowering you can adjust the curtain times accordingly).
If the plants are to be covered in the afternoon then count forward 12 hours from sunrise. If the sun rises at 6:00AM, the curtains should go on at 6:00 PM. Removing the cover at the end of dusk. The cover is removed because moisture builds up on it from dew and plant transpiration. Removing the cover limits the time the plants experience a high humidity environment. In the late stages, mold prevention measures should be taken. The plants can be sprayed with Serenade biological fungicide, Zero Tolerance herbal fungicide, potassium bicarbonate or other fungicides.
In some parts of the country, such as the gulf coast and parts of southern California, the temperature never dips below 45F (7.2C) and plants can be grown all year round. In areas that are slightly cooler but never freeze, a cold frame or unheated greenhouse is all that is required to keep the plants growing. Besides temperature, the problem with growing plants outdoors during the winter is that the dark period is more than 12 hours and the plants are triggered to flower. This is a good time to grow a sativa dominant hybrid because these varieties continue to grow even after they have been triggered to flower.
Another technique is to interrupt the dark cycle with light. The light doesn't need to light the plant for long, just a few sexonds. Think of it as a water spray. You want to get all the leaves "wet" with light, but once they have been sprayed they need no more light. This short interruption of the dark cycle is enough to reset the time count of uninterrupted darkness. By lighting the plants every few hours during the dark period, the plants continue to grow vegetatively and not flower.
When the light interruption stops, the plants immediately start to flower. Plants can be started in August and planting can continue throughout the winter. To increase growth natural light can be enhanced using reflective material and electric lights. Spring starts on March 22 and on that day light and dark share equal time. At the equinox, or shortly thereafter, the dark period becomes too short to support flowering and the plants will grow vegetatively.
To get the best possibly harvest, force spring plants to flower in June. If plants are forced June 1, they will be ready in mid-to-late July. If they are forced July, they will ripen in mid August.
UV-B Light
Ultraviolet B (UVB) light is a spectrum of light that is invisible to us but is visible to insects and some other organisms. In humans it causes suntans and sunburns and is implicated in the formation of eye cataracts. It is also the light emitted by tanning bulbs.
UVB light also affects marijuana potency. The potency of high quality marijuana increases in direct ratio to the amount of UVB light it receives. This is very significant. In California, where the medical dispensaries operate in an unrestricted market, many dispensaries reject fall-harvested outdoor material, deeming it as inferior. They have found it lacks the potency of indoor crops and is a harsh smoke. However, when they were presented with marijuana grown outdoors but forced to ripen August 10, they accepted it as it it were indoor because of its high potency and lack of harshness. I think the harshness results from cool nights.
Indoors, under fluorescent and HPS lamps, gardens receive little UVB light. Metal halides emit a bit more. However, there are ways of supplying your garden with UVB light. Tanning lamps work because of the UVB light they emit. Using tanning lamps will increase the THC content of the crop. Reptiles and lizards require the spectrum to stay healthy. So the spectrum usually comprises about 10 percent of their output. If you wasnt to try tanning lamps they are available on the internet. Use between 5-10% of your total wattage to these lamps. For a 1000-watt garden use 100 watts of special lighting.
Adding UVB light to your garden will enhance your marijuana naturally, without "special formulas" and chemicals.
Green and Blue Light At Night
As plants evolve over hundreds of millions of years they never actually had to deal with separation of light spectrums or unusual lighting regimes. When they receive light it came from the sun in a mixture of spectrums and they could pick and choose which to use. It was only with the advent first of gas and then electric lighting that plants encountered unusual regimens and splintered spectrums.
Plants measure day length using the red light spectrum. While they use other spectrums for other purposes, they are not sensitive to them as far as flowering is concerned. They are almost totally insensitive to green light and for this reason reflect it back to us while absorbing most other spectrums.
Plants' insensitivity to green light can be used to a gardeners advantage. You know that turning the light on in the middle of the dark cycle disturbs the plants' flowering paradigm. The light, HPS, fluorescent and MH lamps all emit red light. Green flouruscent and LED lights contain no red light and will not disturb the dark period. You can go in the garden under adequate light to work, as long as it is green.
Plants use blue light for certain regulatory processes and also for photosynthesis. Chlorophyll absorbs both blue and red light and uses the light's energy to power the complex process in which water and atmospheric carbon dioxide are converted to sugar and oxygen to gas. Blue light does not affect the regulation of flowering.
When blue light is turned on during the dark period, plants photosynthesize but their flowering isn't affected. This results in more growth as the plants produce more sugars. Before LED lights it was difficult to create pure blue light. Instead, most of the time other spectrums were filtered out, which can be an inconvenient process. Try using between 20 and 40 watts of mixed blue light per 1000 watts of regular light. I have done only initial experimentation with this so test this in a limited way of increasing total yield.
Aside from red and blue light, plants also use orange light tor photosynthesis. I haven't experimented with them yet, but orange LEDs might also help increase yield and probably can be lit continuously, just like blues. More on this as the news breaks-or at least as it fractures.
thats it for experimental lighting.
hope it was helpful and remember,
THIS IS ALL EXPERIMENTAL
by Ed Rosenthal
I found this interesting and thought u might too. these entries are verbatim.
CRITICAL LIGHT PERIOD
The 12/12 formula has been accepted without question by growers all over the world. Probably one of the reasons for this was my discussion of the technique in some of my early books. The 12/12 regimen was selected because my co-author an I reasoned that no matter what critical period a variety might have, given 12 hours of darkness it would flower. However most marijuana varieties need fewer than 12 hours of darkness to flower.
If marijuana plants grown outdoors required a 12-hour dark period to flower, they would not be induced to start flowering until September 21, the first day of autumn, when day and night are equal length. They would then ripen 6-8 weeks later. In real life most modern varieties ripen between early September and late October. Budding was triggered 6-8 weeks earlier. For instance, an eight-week variety that requires 55 days from forcing maturity, which would normally ripen on October 1, would start flowering August 1. At that date in San Francisco, sunrise occurs at 5:14 and sunset at 19:18, a total 14 hours and 4 minutes. Dawn and dusk add another 15 minutes of red light. Plants use the absence of this spectrum to measure the dark period. The total lit period came to about 14:20, leaving 9:40 minutes of darkness. The critical period for this plant was 9 hours and 40 minutes. If it was given just 10 hours of dark period daily indoors, rather than 12, it would still flower.
Gardeners growing outdoors who discover the critical time needed to induce flowering can use this information to get more efficient use of their indoor garden. Currently, plants grown under a 12-12 cycle spend half their time in the dark. if the plants have a critical flowering time of, for instance, 10 hours of darkness daily, they can be provided 14 rather than 12 hours of light each day so that they receive almost 17% more energy, which they use to produce sugars used for more and faster growth.
Manipulating Light Outdoors
Sometimes I think nature didnt get it right as far as marijuana ripening is concerned. If it were determined by human needs, the buds would be ready late spring so they'd be readily available in early summer, the party season. If they ripened at the best time for the farmer, it would be in high summer when the weather is warm and the sun strong. Alas, nature has chosen the fall. The harvest can be good if the weather doesn't attack first.
With a bit of effort you can manipulate the outdoor light cycle to grow and flower the plants at your convenience. I think that the best and most convenient time to harvest is during the summer rather than the fall. Buds that ripen midsummer experience much more intense light and much more UV spectrum than fall ripened buds. The intense light gives plants energy to grow bigger buds while the UV light increases their potency.
To force the plants to flower during the summer they need to receive the critical dark period each day. Covering the plants with a blackout cloth each day so they receive 12 hours of darkness pushes the plants into flowering mode. Decide whether you are going to restrict light at the beginning or end of each day. If you restrict light during the morning, place the blackout cloth over the plants just before dawn; then remove it promptly at the appointed time. For instance, if the sun sets at 8:30 PM the curtain, which was placed on the garden at 5:00 AM right before dawn, is removed at 8:30 AM (if you know the plants' critical time period for flowering you can adjust the curtain times accordingly).
If the plants are to be covered in the afternoon then count forward 12 hours from sunrise. If the sun rises at 6:00AM, the curtains should go on at 6:00 PM. Removing the cover at the end of dusk. The cover is removed because moisture builds up on it from dew and plant transpiration. Removing the cover limits the time the plants experience a high humidity environment. In the late stages, mold prevention measures should be taken. The plants can be sprayed with Serenade biological fungicide, Zero Tolerance herbal fungicide, potassium bicarbonate or other fungicides.
In some parts of the country, such as the gulf coast and parts of southern California, the temperature never dips below 45F (7.2C) and plants can be grown all year round. In areas that are slightly cooler but never freeze, a cold frame or unheated greenhouse is all that is required to keep the plants growing. Besides temperature, the problem with growing plants outdoors during the winter is that the dark period is more than 12 hours and the plants are triggered to flower. This is a good time to grow a sativa dominant hybrid because these varieties continue to grow even after they have been triggered to flower.
Another technique is to interrupt the dark cycle with light. The light doesn't need to light the plant for long, just a few sexonds. Think of it as a water spray. You want to get all the leaves "wet" with light, but once they have been sprayed they need no more light. This short interruption of the dark cycle is enough to reset the time count of uninterrupted darkness. By lighting the plants every few hours during the dark period, the plants continue to grow vegetatively and not flower.
When the light interruption stops, the plants immediately start to flower. Plants can be started in August and planting can continue throughout the winter. To increase growth natural light can be enhanced using reflective material and electric lights. Spring starts on March 22 and on that day light and dark share equal time. At the equinox, or shortly thereafter, the dark period becomes too short to support flowering and the plants will grow vegetatively.
To get the best possibly harvest, force spring plants to flower in June. If plants are forced June 1, they will be ready in mid-to-late July. If they are forced July, they will ripen in mid August.
UV-B Light
Ultraviolet B (UVB) light is a spectrum of light that is invisible to us but is visible to insects and some other organisms. In humans it causes suntans and sunburns and is implicated in the formation of eye cataracts. It is also the light emitted by tanning bulbs.
UVB light also affects marijuana potency. The potency of high quality marijuana increases in direct ratio to the amount of UVB light it receives. This is very significant. In California, where the medical dispensaries operate in an unrestricted market, many dispensaries reject fall-harvested outdoor material, deeming it as inferior. They have found it lacks the potency of indoor crops and is a harsh smoke. However, when they were presented with marijuana grown outdoors but forced to ripen August 10, they accepted it as it it were indoor because of its high potency and lack of harshness. I think the harshness results from cool nights.
Indoors, under fluorescent and HPS lamps, gardens receive little UVB light. Metal halides emit a bit more. However, there are ways of supplying your garden with UVB light. Tanning lamps work because of the UVB light they emit. Using tanning lamps will increase the THC content of the crop. Reptiles and lizards require the spectrum to stay healthy. So the spectrum usually comprises about 10 percent of their output. If you wasnt to try tanning lamps they are available on the internet. Use between 5-10% of your total wattage to these lamps. For a 1000-watt garden use 100 watts of special lighting.
Adding UVB light to your garden will enhance your marijuana naturally, without "special formulas" and chemicals.
Green and Blue Light At Night
As plants evolve over hundreds of millions of years they never actually had to deal with separation of light spectrums or unusual lighting regimes. When they receive light it came from the sun in a mixture of spectrums and they could pick and choose which to use. It was only with the advent first of gas and then electric lighting that plants encountered unusual regimens and splintered spectrums.
Plants measure day length using the red light spectrum. While they use other spectrums for other purposes, they are not sensitive to them as far as flowering is concerned. They are almost totally insensitive to green light and for this reason reflect it back to us while absorbing most other spectrums.
Plants' insensitivity to green light can be used to a gardeners advantage. You know that turning the light on in the middle of the dark cycle disturbs the plants' flowering paradigm. The light, HPS, fluorescent and MH lamps all emit red light. Green flouruscent and LED lights contain no red light and will not disturb the dark period. You can go in the garden under adequate light to work, as long as it is green.
Plants use blue light for certain regulatory processes and also for photosynthesis. Chlorophyll absorbs both blue and red light and uses the light's energy to power the complex process in which water and atmospheric carbon dioxide are converted to sugar and oxygen to gas. Blue light does not affect the regulation of flowering.
When blue light is turned on during the dark period, plants photosynthesize but their flowering isn't affected. This results in more growth as the plants produce more sugars. Before LED lights it was difficult to create pure blue light. Instead, most of the time other spectrums were filtered out, which can be an inconvenient process. Try using between 20 and 40 watts of mixed blue light per 1000 watts of regular light. I have done only initial experimentation with this so test this in a limited way of increasing total yield.
Aside from red and blue light, plants also use orange light tor photosynthesis. I haven't experimented with them yet, but orange LEDs might also help increase yield and probably can be lit continuously, just like blues. More on this as the news breaks-or at least as it fractures.
thats it for experimental lighting.
hope it was helpful and remember,
THIS IS ALL EXPERIMENTAL
