When do I spray my plants with sts solution

hi all I’m growing 5 of my plants outside in the ground and have another outside in a pot I plant to spray with STS solution to create female pollen and then take inside and wait to collect the pollen. I live in Massachusetts and would like to know when I need to start spraying. I’m thinking sept 25th according to this calendar since its 12hr of light but want a second opinion or 2 Sunrise and sunset times in Boston, September 2023
thx steve

Id wait until i saw female hairs forming. Id make sure to isolate this plant also if ot came fromr the outside.

I was asking because I read that you spray once you change the light cycle to 12/12 , so your saying once it starts to show its sex you can spray…thx

Spray one branch when you see evidence of the plant flowering. The branch will produce male flowers for male pollen that you use to pollinate female flower for feminized seed.

Outdoor plants don’t care about the exact length of daylight, just that daylight time has declined enough for plants to identify days are getting shorter. Here we typically start seeing pistils on Outdoor plants in mid August.

There is also sometimes issues with getting mature seeds from the pollen donor. You may have to collect pollen from this plant and use it to pollinate a different plant on your next grow to get the most out of it.

thx, I plan to pollinate one at another location