Are we sitting comfortably.. Let me start by saying that these are personal observations, that i have made in the short time that i've been growing AutoFlowers.
First lets talk about Tiering V Straight to final pots. I always wondered about this one, can it really be a good idea to put the seeds in such a small restricting container as a 32oz cup, well it would appear, if recent science on the subject is anything to go by, the simple answer would be no. Here is an artical on the subject (Originally posted by TaNg)
http://www.bbc.co.uk/nature/18612661
As you can see plants from seed can fill a pot in as little as two weeks. Since i first read this, i have been checking the bottoms of my pots to see when roots appear. And the results are conclusive. My 7.5L pots can be filled as early as 11 days and my 14L as early as 14 days. So if you are growing using the tier method you maybe severly restricting growth (some people are not transplanting until 21 days). By which time the damage may already been done and the plant may not reach its full genetic potential. My advice would be to start in the biggest pot you can ge your hands on.
Next i would like to talk about when to a switch to bloom nutes, this seems to be another subject that needs to be addressed. I started my AutoFlower adventure after seeing Seymour Bubs TD grow. And have been following his methods on that grow closely, and what i found was that he had swithed to bloom nutes only 10 days afte showing sex. But the collective wisdom on this is that if you sart feeding bloom nutes early you will stop the vertical growth. But as we all looked on in awe, that this was, far from true. He grew a complete monster that continued to grow, with no sign of the early switch stoppig the vertical growth. So i tried it myself on the last two runs of TD and AutoXtreme, i switched them both 10 days after sex, could i restrict the vertical growth, the sinple answer is no, in fact the AutoXtreme got so out of control height wise i had to supercrop it. What i found was that i had better bud development, than i had on my first TD grow. I would love to hear from anyone who is switching early and managed to stop the vertical growth. The reason i'm interested, is that i grow in a small space height wise and thought that doing this would give me smaller plants, but alas they just keep growing and as i mentioned before i have to resort to things like supercropping and LST.
One last thing i would lke to mention is about hot soils, I keep hearing that autos don't like soils that are hot, like BioBizz All Mix which seems to be one that gets a lot of bad press, but here's the thing, it's what i used on my first TD ScrOG grow, and we all know how that turned out, so i though, ok i was lucky that time, but being someone who likes to experiment, i tried it again this time with one of the StarRyders. Did it burn it no, did it slow its growth no. it's the biggest plant in the grow room at the moment.
So i think we have to at least give this soil a look in. And not rule it out as a viable starting soil for new growers in the UK. I think the key is to to start them in Root Riots, seems to give the seed that little boost it needs in the first couple of days.
Anyway i hope you find some of these personal observations useful, and if you have completely different experiences from me i would love you to share them.
Cheers
Hazy