Here's one of my favorite on site links that I must have referenced a dozen times during my first couple of grows,
https://www.autoflower.org/threads/when-to-harvest-autos-your-leaves-will-tell-you.4889/
Hopefully that helps. I also like to use the pistils as an indicator. As the plant matures, the calyx will swell up and swallow most of the pistils. Seeing how yours are big, fat, white, gorilla pistils - I'd venture to say you can let her swell and push straight water for the rest of her life. You won't believe how much they can swell in 5 days. If i was forced to guess, I would say 10 - 15 days.
It's hard to say why your 3 Bear ended up on the smaller side without going through your thread with a fine toothed comb. One things for sure, your other plants look proper ! Knowing when to water in soil can be difficult, especially with fabric pots. A great tip is to constantly pick up your pots. Every time you look at them pick them up, and in no time at all you'll be referencing the weight of your soil to water instead of trying to guess or rely on visual cues.
@Autoflowa - do you have negative air flow going ? Pulling cool air from the bottom and blowing hot air out of the top ?
Have you tried adding Silica to your feeding routine ?
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