Photoperiodic responses & when to plant outdoors

monkz

monkz

Well-Known Member
So this year will be my first outdoor grow. There seems to be a lot of rumor and myth about when exactly to start your plants outdoors, so I decided to do my own research into it. Many say it's fine after the spring equinox (March 20th in the northern hemisphere), while others say it can be done earlier, as soon as the last frost is over, whereas others swear by only planting outdoors when the actual daylength is more than 14 hours.
If you're like me, and your region doesn't experience temperatures lower than 10c in the winter, frost is the least of your worries, so when do you plant? Cannabis is a photoperiodically responsive plant which needs around 14 hours of 'light' to keep it in a vegetative state. But here's the thing, 'light' doesn't directly correspond to daylength. Photoperiodically responsive plants can also detect civil twilight, thus meaning that you also have to take into account the short periods both before sunrise and after sunset.
I germed my seeds yesterday (April 5th), and my guess is that they'll have sprouted and be outside within the next 4-7 days. The light period in my area, including civil twilight, is just under 14 hours at this moment in time, but it will do :)
If you wanna check out twilight times in your area, here's a link to a good site with tons of info: www.timeanddate.com

All comments welcome :)

Peace,
Monkz.
 
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ttystikk

ttystikk

Well-Known Member
Phototropic strains will flower with as little as 10 1/2 hours of uninterrupted darkness, so the fourteen hours of daylight (including 'civil' twilight- interested in a definition here) seems a good yardstick.

Autoflower strains won't care.

For those in greenhouses, spring is a great time to flower because of reduced need to do active light deprivation, ie, dragging a tarp over the greenhouse before dusk.
 
monkz

monkz

Well-Known Member
ttystikk said:
Phototropic strains will flower with as little as 10 1/2 hours of uninterrupted darkness, so the fourteen hours of daylight (including 'civil' twilight- interested in a definition here) seems a good yardstick.

Autoflower strains won't care.

For those in greenhouses, spring is a great time to flower because of reduced need to do active light deprivation, ie, dragging a tarp over the greenhouse before dusk.
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Totally in agreement, let me explain the twilight part. Basically there is actual daylength, i.e. the time between sunrise and sunset, and then there are the twilight phases. There are 3 phases of twilight, both before sunrise and after sunset. These are; civil, astronomical, and nautical twilight (all in order from brightest to dimmest). The further the Sun is below the horizon, the dimmer the twilight, and photoperiodically responsive plants will pick up only on the civil twilight.

Here's one of the articles I've read on this, if you're interested; https://extension.umass.edu/floriculture/fact-sheets/photoperiod-control-systems-greenhouse-crops

Monkz :)
 
B

brimck325

Well-Known Member
I vegged at 15/9 last year n it worked out well, but I waited until beginning of May to put em out. I,m round the 40th'
 
treemansbuds

treemansbuds

Well-Known Member
monkz said:
So this year will be my first outdoor grow. There seems to be a lot of rumor and myth about when exactly to start your plants outdoors, so I decided to do my own research into it. Many say it's fine after the spring equinox (March 21st in the northern hemisphere), while others say it can be done earlier, as soon as the last frost is over, whereas others swear by only planting outdoors when the actual daylength is more than 14 hours.
If you're like me, and your region doesn't experience temperatures lower than 10c in the winter, frost is the least of your worries, so when do you plant? Cannabis is a photoperiodically responsive plant which needs around 14 hours of 'light' to keep it in a vegetative state. But here's the thing, 'light' doesn't directly correspond to daylength. Photoperiodically responsive plants can also detect civil twilight, thus meaning that you also have to take into account the short periods both before sunrise and after sunset.
I germed my seeds yesterday (April 5th), and my guess is that they'll have sprouted and be outside within the next 4-7 days. The light period in my area, including civil twilight, is just under 14 hours at this moment in time, but it will do :)
If you wanna check out twilight times in your area, here's a link to a good site with tons of info: www.timeanddate.com

All comments welcome :)

Peace,
Monkz.
Click to expand...
If you left those seeds/seedlings in a greenhouse now you'll be fine, I'll explain....
.
Marijuana takes 5-8 weeks to show sexual maturity, no flowering will occur until they show their sex. That's 5-8 weeks away when the datlight hours will be over 14 hours, counting the dawn and dusk hours. I live in central Ca, years past I've started the seeds in my greenhouse the first week of March with no issues (lie, I had 1 strain start to flower on me after 6 weeks, Medijuana) no artificial lighting was used.
I put the plants into their 200 gallon smart pots during the waxing moon phase during the month of May (waxing moon phase for May this year will be 10th-24th, my target date is May 14th) If you do this you'll be fine.
Good Luck,
TMB-
 
monkz

monkz

Well-Known Member
treemansbuds said:
If you left those seeds/seedlings in a greenhouse now you'll be fine, I'll explain....
.
Marijuana takes 5-8 weeks to show sexual maturity, no flowering will occur until they show their sex. That's 5-8 weeks away when the datlight hours will be over 14 hours, counting the dawn and dusk hours. I live in central Ca, years past I've started the seeds in my greenhouse the first week of March with no issues (lie, I had 1 strain start to flower on me after 6 weeks, Medijuana) no artificial lighting was used.
I put the plants into their 200 gallon smart pots during the waxing moon phase during the month of May (waxing moon phase for May this year will be 10th-24th, my target date is May 14th) If you do this you'll be fine.
Good Luck,
TMB-
Click to expand...

I agree on what you say about plants showing their sex, which is usually, as you said, at 5-8 weeks of age. However, as I said earlier, you also need to take civil twilight into account because your plants will be fine well before the waxing moon phase and will not flower. For example, on the first day of this year's waxing moon, daylength is 14hrs and 1min at my location, whereas total light (including, as i said, civil twilight) is 14hrs 58mins, so I could have got away with planting up to a month earlier, which is exactly what I will be doing :)
 
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treemansbuds

treemansbuds

Well-Known Member
monkz said:
I agree on what you say about plants showing their sex, which is usually, as you said, at 5-8 weeks of age. However, as I said earlier, you also need to take civil twilight into account because your plants will be fine well before the waxing moon phase and will not flower. For example, on the first day of this year's waxing moon, daylength is 14hrs and 1min at my location, whereas total light (including, as i said, civil twilight) is 14hrs 58mins, so I could have got away with planting up to a month earlier, which is exactly what I will be doing :)
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Exactamundo my friend!
Dawn & dusk hours = civil twilight.
TMB-
 
monkz

monkz

Well-Known Member
treemansbuds said:
Exactamundo my friend!
Dawn & dusk hours = civil twilight.
TMB-
Click to expand...
Sorry mate I didn't know you were referring specifically to civil dawn and dusk, because you can also have nautical and astronomical dawn&dusk, basically a synonym for twilight, which as I said, has three stages. So yeh lol, glad we meant the same thing :)
 
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