TheRealGreens
Member
So I have Ed Rosenthal's Marijuana Grower's Handbook and there a part in here that states this:
" The amount of UVB light a plant recieves affects THC and terpene prduction. Plants grown under higher UV levels are more potent.
The amount of UV light that an area recieves is determined by latitude, season, climate, and weather. Light reaches the equator most directly, and is the most intense. As the latitude increases light reaches Earth at a more oblique angle so it becomes less intense.
Throughout the northern hemisphere, which includes North America and Europe, UV light is at its lowest levels in December and January. After these months, the levels start rising. The further from the equator, the longer it takes to peak, the shorter the peak period and weaker the light.
For instance, in San Francisco ( latitude 37.75 ), UVB reaches its peak with a UVB index between 9-11 around May 15th. It stays there until around August 15th. By Sept. 1 it drops to 8 and by Oct. down to 6.
If you can ripen plants during the peak UV period the plants will be most potent. As the season wears on and the UVB levels decline the marijuana does not attain the same potentcy.
Using this information, no matter where you live, even in the far north you can grow potent
plants using light deprivation, so that plants ripen at the peak period rather than late in the season.This Chart can help determine a planting strategy."
This Pic is a bit crappy but it is the chart showing UV indexs of 2008 in Honolulu, HI lat N 21(red bar at top and I'm going down), Jacksonville,FL 30 N lat(pink), Raleigh, NC 35 N lat(yellow), Omaha, NE 41 N lat (purple), Seattle, WA 47 N lat(green), Anchorage, AK 61 N lat(blue the last bar). Now the chart on the x-axis(the one going sideways) shows months and y-axis is UV index rating 1-15.
Also says you can go to www.weather.gov and get UV info there.
I have added one to my grow to test this theory.
" The amount of UVB light a plant recieves affects THC and terpene prduction. Plants grown under higher UV levels are more potent.
The amount of UV light that an area recieves is determined by latitude, season, climate, and weather. Light reaches the equator most directly, and is the most intense. As the latitude increases light reaches Earth at a more oblique angle so it becomes less intense.
Throughout the northern hemisphere, which includes North America and Europe, UV light is at its lowest levels in December and January. After these months, the levels start rising. The further from the equator, the longer it takes to peak, the shorter the peak period and weaker the light.
For instance, in San Francisco ( latitude 37.75 ), UVB reaches its peak with a UVB index between 9-11 around May 15th. It stays there until around August 15th. By Sept. 1 it drops to 8 and by Oct. down to 6.
If you can ripen plants during the peak UV period the plants will be most potent. As the season wears on and the UVB levels decline the marijuana does not attain the same potentcy.
Using this information, no matter where you live, even in the far north you can grow potent
plants using light deprivation, so that plants ripen at the peak period rather than late in the season.This Chart can help determine a planting strategy."
This Pic is a bit crappy but it is the chart showing UV indexs of 2008 in Honolulu, HI lat N 21(red bar at top and I'm going down), Jacksonville,FL 30 N lat(pink), Raleigh, NC 35 N lat(yellow), Omaha, NE 41 N lat (purple), Seattle, WA 47 N lat(green), Anchorage, AK 61 N lat(blue the last bar). Now the chart on the x-axis(the one going sideways) shows months and y-axis is UV index rating 1-15.
Also says you can go to www.weather.gov and get UV info there.
I have added one to my grow to test this theory.