autoflower... stressed out and went into flower even earlier than normal. Bright side - still have 2-3 weeks of vege growth coming before it completely stops. Do your best to get growth pattern back to normal. Symptoms are rough.. maybe S-def and P-def? but could be lockout or pH too.. ramifications of poor watering habits due to pot size is also in the realm os possibility as a cause or exacerbating the existing problems.
Also at least recently you've been giving too much light as the top 2-3 nodes basically have leaves pushing on each other. Probably a combination of light and nutrition issues, best guess.
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Big pot, tiny plant is a bad idea, even with autoflowers. If a grower can't pot up without decimating the rootball, should find a new hobby. I don't say that to be mean. I fully have confidence that you can perform a simple task without damaging the plant or stunting it. That's just commentary on cultural beliefs that are absurd. I don't even have decades of experience, but after 400-some 'transpolants' i've yet to see 1 plant have a negative effect from it. What we do with potted plants is better described as "potting-up" because a transplant of an outdoor plant is drastically different and involves cutting off 95% of the root system, which is incredibly stressful. However, gently placing a plant in a slightly larger pot and covering it with more medium is not stressful at all when done right and easy to do. Make sure there's enough moisture and roots to hold it together and it's foolproof.
it's incredibly difficult to water properly when you have a large pot and tiny plant. with autoflowers, every less-than-optimal thing you do can have a much greater impact than with a photoperiod. There is no room for error with autoflowers. You can't just vege it longer to make up for any problems experienced.
i'd suggest growing photoperiods until you are supremely confident at keeping plants healthy seed to harvest. Learn all the ancillary stuff like potting up. Then, if you still want to grow autoflowers, that's the time to grow them.. when you won't severely impact outcomes with a small and large mistakes piling up.
when you hinder a photoperiod, you can simply hold off on switching to flower until things are fixed... much more forgiveness, which is beneficial early in the learning curve. No worries. It's not rocket science, and you'll learn quickly.