Yes, there is a lot of differing opinions when it comes to growing cannabis. And some are okay and some aren't.
While 4.5 may be closer to 6.0 than 8.0, I am not sure why you believe that 6.0 is a pH to aim for? It is too low for soil grows and too high for hydro grows. Are you certain your distilled water is that low? Distilled should be close to neutral, which is 7.0. However for seedlings, the water will not need to be pH'd unless your water is way out of whack. IMO, a pH of 4.5 is too acidic for anything and I do question that pH reading from distilled water. How exactly are you measuring it? Some pH meters are not worth the space they take.
>>>>>>>I think I responded elsewhere THG but just in case... It's a nice metre, milwakee M820, 3 days old, I think I forgot to rinse the tip or measured the wrong sample. I re-checked today and it's 6 - 7ish... I do ramble on about the metre somewhere else too though, I'm kind perfectionist stoopid so I'm still frustrated with it but gotta be better than pool test strips I was using
I never ever use products like Thrive for seedlings. I have never found the need. IMO, it is a good idea to know what you are giving plants and why.
>>>>>>>> my seeds were all popping up and just standing there refusing to grow. I >was crying about it at the grow shop when I went in for mat and >presented them with another opportunity to sell me crap I didn't need.
Just someone saying they do it is not good enough. There needs to be a scientific reason that is plausible. I, like Rosebud grow organic when I grow soil. I sow directly into my medium, which is organic. And do not give the plants anything that is not also organic.
Different plants are going to be able to go different amounts of time before you feed. A good rule of thumb is to feed when the cotydons start yellowing. And then, you start at a low dose, like 1/4 strength and slowly work up. Do not use soil that has nutrients or those moisture crystals in it. I do not use ANY Miracle Grow or Scott products because I hate Monsanto so much. When you do start feeding, I recommend using something formulated for cannabis.
Growing cannabis is complicated and it does take a lot of time, money, skill, knowledge, and love. And, of course, to make it more complicated, there are a lot of differing opinions. Why not tell us what you have in the way of equipment, how your space is set up and about your grows in general...medium, nutrients, temps, humidity, etc, etc.