A topic titled "
Preventing Autos flowering early outside" shows what needs to be done.
Every auto I've tried to grow outdoors ends up flowering way too early. like 6 inches early.
How do I reduce the stress placed on autos when transplanting so they don't flower prematurely?
That has to be one of the easiest questions to answer in a long time. An auto-flower will start its flowering when the plant has more flowering hormones than vegetating. That means that the grower will have to work overtime if they want to prevent the plant from doing what it is genetically designed to do and still have a 99% probability that they will fail.
Plan ahead to take advantage of what nature will do.
Want to reduce the stress placed on the plant when it is transplanted? Basically, don't transplant. Select the spot where you want to grow the plant and put the seed into the ground there when it is time.
...ends up flowering way too early. like 6 inches early.
Sounds like a size problem and not early flowering problem. Are you are worried about the amount of harvest? Not transplanting will help. Following a fertilizing schedule using a decent fertilizer will help some more.
I'm in New York, zone 7 a/b.
The USDA zones available as a way to help with figuring out which
perennial plants should survive an average winter in that zone. Disregard the zone maps since they are confusing the issue and you will be planting, growing, and harvesting in the warm months. You do not even need to know the average last spring and average first fall frost dates but a good grower will learn what they are anyway.
Since you brought it up, Zone 7a & b in your state is pretty much the New York City and areas within about 25 miles. The last frost is about April 5 to 15 and first fall frost will be October 20 to Nov 10th. Remember those are just averages.
Any other transition considerations re fertilizer, time of season, etc.
Nothing will beat a quality fertilizer with easy to use measuring and scheduling. Do not choose by price or pictures of pretty girls on the package.
"Time of season" is easy; all that you have to do is plan ahead. Do not start by figuring out when to plant. The first thing to do is to figure out the best time to harvest. Since September has the highest average monthly humidity levels for your state go with a harvest in mid to late August. Let us pick August 15th for harvest.
The average auto-flower still seems to have an eight week flowering window so back-track 9 weeks which allows an extra week for glitches in the Matrix

. That would mean making plans based on the plant starting to flower about the 13th of June.
Since the average time between germination and start of flowering for autos is 4 to 5 weeks that means you should have the spot picked out and prepped by May 12th. Put the seed in the ground and if all goes right it should be sprouting by the 15th.
If the seed takes a couple of days longer to sprout or if it sprouts on time but is slow in getting started you have that extra week to play with which is why I recommended 9 weeks to allow for glitches. Actually, I gave you another two weeks or so since you could back-track from the 1st of September if you wanted. Keep in mind that September has the highest average humidity for New York state.
Longest day of the year is the first day of Summer which is June 20th. You will have the best window for quality light levels between the 15th of May and the end of August. Good light should mean great growth and quality at harvest time. And great growing temperatures come to think of it.
I am running my "
On Schedule" photo essay-journal based on back-tracking from a planned harvest date using photo-period plants. I know when the length of days will start them flowering. I wanted them a certain size and height. I had to figure when to get the plants into the final pot to get root and above ground growth. I planned on when to get them outside to take advantage of sunlight. I took cuttings for a clone and planted seeds ahead of time and then had to keep them inside. That meant stalling them with making them get root bound and then having to root prune. Had to figure in transplanting a couple of times because there is only so much root work that I wanted to do. I had to give lower fertilizer doses to keep their size down. Controlled their growth by giving lower amounts of water. But it was all planned ahead after back-tracking from an October 10th to 15th harvest window to see if I could beat the Bud Rot issue.