Cannabis plants DO NOT take water "from the air", this is what the roots are for.
Roots grow as soon as the seed sprouts, so if your plant is from a seed and alive, it has roots.
Only clones don't have roots, at first.
Misting clones and/or keeping them in high humidity prevents the leaves from drying out, but again, they DO NOT take water into the leaves from the air!
Transpiration only works one way - water in through the roots, up the stem and OUT through the leaves........it does not work in reverse.
Your lack of growth is probably down to inadequate lighting, - if you are only using 24 watt veg lights, this is barely enough to sustain life.
Low temps and/or incorrect soil conditions will also slow growth.
A pH of 7.8 is definitely a problem, your pH in soil should be between 6.2 and 6.8.
A pH of 7.8 will prevent the availability of nearly all the vital elements in the soil that your plant needs to access for growth.
I am also not a fan of dry amenmants this early in a grow, they need a lot of time (4-6 weeks) to break down and become bio-available to your plant and I much prefer to use liquid nutrients that are instantly accessible by your plant. The pellet type nutrients also need constant moist conditions to break down and become activated and one thing cannabis does not like, is being constantly moist.
The fertilizer you are using might be fine for tomatoes (4/4/4) but you should really invest in some cannabis specific, liquid fertilizers.
Unfortunately, since you are growing autos and they are already approaching 4 weeks of age, flowering won't be far off............so whether to continue or not is up to you...........but don't expect a bumper harvest.
Next time, start with a balanced soil mix in the correct pH range (with less peat), use your LEDs from day one and invest in some proper cannabis nutrients and your grow should be much more successful and rewarding.
I would also suggest growing feminized photoperiod plants next time, they are far more forgiving and YOU can determine when they flower, once YOU are satisfied with their size, health and vigor.
Autos actually require a lot a skill to get the best results from and are not the best choice for new growers........despite what the marketing hype might be suggesting.............unfortunately.
Hope this helps, Organoman.
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