Thanks for the input. It's hard to tell. I was watering about 5 days apart and each time the soil was dry an index finger deep. Do you think I should have used smaller pots? (These are 5 gallon)
like i said i don't grow auto's so i can't really give you info on pot sizes and if potting up is beneficial due to how auto's grow. it just takes practice for me i had to push myself to underwater more even though it is literally hard because i want to fucking water them daily in mass amounts lol. what i think you should do next time is grow photo's. to me if you can grow photo's fairly well you should easily grow auto's no issues.
what i noticed when my plants did get underwatered that one time and i knew they were going to need watering but i simply forgot to water them is that the leaves and the stem connecting to the leaves felt flimsy as fuck. like something sucked the life out of it. when i over water the leaves are droopy but the stems seem kind of on the stiffer end as if their is water in it. kind of like a ballon effect. a ballon with nothing in it is super flimsy add something like water or air it gets stiffer. add more water/air it swells up.
just based on the picture though it does look like over watering. you say you water every 5 days? try cut it back to every 6 days or 7 even and see how it feels at day 7 then try to water. 3 inches of roots is literally nothing to these plants. grow my plants in solo cups for i think about 2 weeks max plants were fairly small before i transplanted. but the root system was already coming out the bottom/starting to.
i advise to grow photo's because you have the liberty to keep them in veg and experiment more compared to autos due to how auto's grow. other then that it's literally just a learning process for everyone. some people are good at it others take more time but eventually you will get the hang of it. it's literally an easier process imo then dealing with nutrient issues man when you get to that point it just becomes a fucking headache to me at least.