Humidity Problem & Possibly Under-Watering

Yes, sort of a contradictory title (I think). 1st time grower here - exactly 4 weeks into growing autoflowering white widow strain.

Up until recently, I had no problems controlling temp and humidity, was consistently hitting 40-55 RH, low to mid 70s fahrenheit with my indoor grow tent. I was watering daily, clean water one day, nutrient mixed alternating days, with just 1-gallon of water total split between these three pots (see pictures). I went away for a few days so I did a watering on Wednesday night and had a friend water them on Friday (fully supervised on video chat lol). They grew incredibly fast in just those 4 days so I started doing 1.5 gallons between these three pots.

Long story short, my combo of new problems:
1) I can't get run-off for shit. I get almost zero run-off from this amount of watering and heard that I should be getting consistent run-off, I'm using Smartpots and have them in plastic trays but they're not lifted off the ground... am I watering enough? I've been doing it very subjectively and just feeling the plant and soil so I don't overwater... I'm fearing I'm under-watering them. Is that the case?
2) Conversely, I now have consistently high humidity readings (70s RH) but the plants look how they look in the posted photos. Could my hygrometer potentially be fucked up or do I have a problem that needs solving? Meter started reading super high over the past day or so. I turned my exhaust fan up a bunch and opened vents to start circulating new air in.
3) the damn white spots on the leaves. I initially thought this was residue from watering with nutrients but I am more suspicious of it being white mold... what are your thoughts? How do I mitigate this? I know I can google around so I won't be offended if you tell me to fuck off on this one but could use some expert pointers.

Thank you everyone!

Can you give some more info on your grow?
Lights, ventilation...

GBAUTO said:

Can you give some more info on your grow?
Lights, ventilation...

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Sure thing. Using a KingLED "1000W" LED Light, I had it approximately 18 inches above the plants but they've been growing really quickly now and they started to get closer to 12 inches away so i raised the light much higher. 2x4x5 tent, AC Infinity 6 inch fan, using it as an exhaust so I've got a few vents open plus the door slightly in order to pull air through continuously. Am i missing anything helpful?

perc30 said:

Sure thing. Using a KingLED "1000W" LED Light, I had it approximately 18 inches above the plants but they've been growing really quickly now and they started to get closer to 12 inches away so i raised the light much higher. 2x4x5 tent, AC Infinity 6 inch fan, using it as an exhaust so I've got a few vents open plus the door slightly in order to pull air through continuously. Am i missing anything helpful?

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Using Happy Frog soil, went light-to-no nutrients initially, now I'm using Big Bloom and Grow Big every other watering. Obviously watering quantity is something I've not been 100% certain on, as you can see in my original post. My pH measurements have been consistently 6.2-6.5 range on the mixture im using. White widow autoflower seeds from ILGM, exactly 4 weeks from when i germinated and put them in the soil

perc30 said:

Using Happy Frog soil, went light-to-no nutrients initially, now I'm using Big Bloom and Grow Big every other watering. Obviously watering quantity is something I've not been 100% certain on, as you can see in my original post. My pH measurements have been consistently 6.2-6.5 range on the mixture im using. White widow autoflower seeds from ILGM, exactly 4 weeks from when i germinated and put them in the soil

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As the plants grow, youll have to start watering with more water to achieve runoff.

The root system is growing, and the absorption rate changes with the size of the plant. I give mine in 3 gal/5gal pots about half if not 2/3 gal of water per watering (about every 2/3days) .

2. Did you notice a decrease in the RH with the fan being turned up? Are you exhausting into the same room as the tent, or to outside?

3. White spots, I get them on my plants, I believe some of it is minerals from the tap water residue. Just keep am eye out for bugs.

Looking good, keep up the good work!!

Nefrella said:

As the plants grow, youll have to start watering with more water to achieve runoff.

The root system is growing, and the absorption rate changes with the size of the plant. I give mine in 3 gal/5gal pots about half if not 2/3 gal of water per watering (about every 2/3days) .

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Okay this is really helpful context. So if you're doing 1/2 to a 2/3 per pot, i'm using 5 gallon as well, then i've JUST ramped up to that amount, from using 0.5-1 gallon across all 3 pots total. At this very moment, my soil is as wet/moist as its ever been, sounds like i need to chill for a day, let these plants do their thing and when things start to dry out again, reassess and feel a little better about this amount of water (at least til they get bigger). I'm just happy these guys have really taken off, they're growing so fast now! don't wanna fuck it all up

perc30 said:

Okay this is really helpful context. So if you're doing 1/2 to a 2/3 per pot, i'm using 5 gallon as well, then i've JUST ramped up to that amount, from using 0.5-1 gallon across all 3 pots total. At this very moment, my soil is as wet/moist as its ever been, sounds like i need to chill for a day, let these plants do their thing and when things start to dry out again, reassess and feel a little better about this amount of water (at least til they get bigger). I'm just happy these guys have really taken off, they're growing so fast now! don't wanna fuck it all up

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Exactly. Wait till its dry to at least an inch or so then douse em lol.

They're looking great, keep it up!!!

I do a simple test-pick up the pot.
Is it heavy or light?
If the soil is dry and the pot is light, it's time to water.