I made a mistake and planted full size plants in March here in Florida.
I have a feeling they won’t produce much if at all because plants don’t bloom until September here. I have limited space.
Do you think I should throw out the big plants and plant auto’s in their place?
Welcome to the community, @Rosie12! 
I’m loathe to waste anything, so IF they are healthy, I would consider grooming/training them into massive low, bushy plants and get a big bonus in late October or early November.
Of course, a lot depends on your specific situation and all…
They will likely get pretty big with a 6 month veg. You could take a clone or two off them and start those in its place.
Thank you. I tried trimming a big plant for many months. Nothing happened. Someone said they were cut back too much. I don’t know.
I have seen than online but that guy was going OTT. You gotta think how big industrial farmers from their plants I would work on getting really healthy roots and maybe adding some silica to improve stems… if they’re strong enough to hold the bud they should bud very nicely. If not comfortable defoliating just skip that especially since you’re outside anyways, you’ll get plenty of light as the sun moves (vs us indoor growers with stationary light)
If you can, just keep them healthy. A plant that’s already large should yield a lot come flowering complete. I’m not familiar with how long the season is there, but September seems early too.
Same situation I now face except where I have mine it’s only getting maby a total of 5 to 6 separated hours of light. What will happen?