Estimating Harvest Date???

First time grow question...

The seed / strain details for the seeds I bought list Flowering Time as: 60-65 days/1st week Oct. (south), mid October (north). With flowering time beginning when the 12 / 12 light cycle begins.

My plants are outdoors and doing very well. Charts on the USNO site indicate that for my location, Sept 25/26 are the dates on which sunset is 12 hours after sunrise. Is this the date that marks the beginning of the 12 / 12 light cycle?

If so, 60-65 days would put the harvest date at Nov 29 - Dec. 4 .... way past mid-Oct and certainly after the point at which we begin to experience regular frosts. Do I plan on a mid-Oct harvest or do I allow my ladies to continue to grow until frost is emminent (which, historically has been end of Oct to mid-Nov.)?

Thanks for the help.

Excellent question, I'm at 45°N and 12/12 starts at the exact same time for me, I planted late last year and my plant didn't start budding until about the 2nd week of September, I ended up chopping her prematurely on Oct 26th because a week's worth of soggy rain set in afterwards, luckily we had a beautiful October up until then, this year I'm way ahead of schedule and very pleased with the veg results so far as they've been out since May 7th and are already enormous, I've got Early Skunks that should be ready by Oct 1st but if I plan on the 12/12 it'll be Thanksgiving before I harvest, does early planting make the difference? I think age and not only light plays a role, any help appreciated.

I'm growing my first plant outside so don't know what to expect, but I've wondered the same thing. Also, what constitutes the 12 hours of light ~ direct or just dawn to dark? Mine is in a patio where the afternoon sun shines directly on it only about 7 hours a day (right now). Isn't harvest season in October in all areas in the US? I've thought about this before and got to the point that the days get shorter aftere June 21 with summer solstice half way. That's nature and I'm not sure you can tally it with a calendar. I hope you keep a diary with the days it starts to sprout, etc. Then we'll all know.

most strains that arnt autoflowering need 12 hours of complete uninterupted darkness to start to flower some people place barrels over them for cupple hours before dark to trigger early flowering

i just checked on a site and my plant will probably start to flower late august-mid september, meaning late october-mid december... wayyy too long for a michigan outdoor, well, we'll see

I'm definitely going to have to use some kind of barrel because my patio is never completely dark. Mine's potted and if she doesn't get too huge, I'm thinking of bringing into a dark bathroom at night when her flower season starts. Would that work?

Update .... just found this post from an experienced poster that I believe addresses this question. Thanks Angus!

" ... There isn't a set light schedule that 'snaps' plants into flowering. They begin to flower after they sense the days becoming shorter.

12/12 is only used indoors. The sharp contrast between eighteen and twelve hours of light immediately induces flowering. Outdoors, the change is very gradual.

Your plants will start flowering, probably, sometime in early august. Which would be like 13¾/10¼.


If you took 30 seconds to do a search you would see that five people a day ask when 12/12 starts in their area, and are all told that it doesn't matter. I just wanted to give you another chance to find the info for yourself."