Yes, this is in flower, but barely. I’m saying you should run high humidity and temps through veg, and your plant would be much bigger than this. I’m giving that advice more toward your next run, however... you can still safely run high humidity for the next many weeks. I’d run recommended temps until the buds start to mature and get fat, and then drop the humidity only below 40% in the last week or two to prevent mildew and bud rot. You’re nowhere close to that. You have at least 4-6 weeks before you get to the end stage.
Now may be a good time to learn about VPD. Here’s a chart that’s as good as any.
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My advice is to keep it in these RH ranges with a temp between 28-30c, so 70-80% RH. In the last few weeks, ignore the chart, and park the RH as low as you reasonably can without plummeting temps.
The reason for this is that high temps and humidity mean rapid growth, and higher-than-average temps work great with LED for reasons related to spectrum. However, the last few weeks of flower are the most dangerous for a new grower, so during that time I recommend dropping RH purely for safety. It sucks to lose your first crop to rot.
If had a few grows under your belt, my recommendation would actually be to stay in 1.0-1.2 kPa VPD through harvest, and be real careful about airflow, filtration, and ventilation. That’s like keeping the pedal down and bottle on through the finish line, but it isn’t without risk.
This won’t necessarily directly help with nitrogen toxicity, the nutes are in the soil and I don’t like to try and reset soil. But the plant is going to start transpiring a lot more rapidly and you will see some real growth, and the plant will start to dry that pot down and you can start running some of the nutrients salts out of there... it’ll let you max out what you can get from this girlie. Run it until the pot is very dry, then drench it well to good runoff, and repeat.
I dunno how many days until you should water... it depends on what’s going on under the surface with the root system. Let it go until it’s very dry. Then water to very significant runoff. If you put 2 gallons in, you want a half gallon to run off for the next little bit.