repot and add compost to fill what you need and you should be fine for a while without nutes.
When you'll need nutes you'll be in full bloom and a dose of high P bat guano should solve the issue.
Water with tap water that sat in a bucket without a lid for 24 hours, or had been aerated for 4 hours using an air pump. I use my dog's water bowl when it needs changing.
I sometime aerate my dogs water too - he doesn't need that chlorine either.
If your water is not chemically treated you can use them off the tap.
You would need less than a tablespoon of guano for all your grow and a small bag of compost which is fairly cheap.
You would NOT need to PH you water or check for EC. You would also need to water less frequently as compost holds a lot of moisture.
You WOULD want to flush a week before harvest and hold on any guano you add for the last MONTH of growth.
Thats the organic way. You would probably yield a bit more with chemical fertilizers, but you would more than likely spend more money on nutes and surely if you'll buy a PH pen, pH down solution and all those other things.
If you only use minute (ASK before you use) amounts of guano you really don't need to mess with much about fertilizing your plants.
In either soil, soilless, chem or organic you would want to use the biggest pot you can, volume wise.
I'm currently growing in a mix of potting soil, activated char. (had a lot of leftovers), lots of composts and earthworm castings (another kind of compost, better but more expensive), a bit guano and I water it with dechlorinated water and the occasional compost tea (google AACT).
Check it out -
https://www.icmag.com/ic/showthread.php?t=185590
I say the best way to manipulate your plants is a SCROG.
Set it LOW (10 cm tops above the final pots), put the lights at a proper distance (3" from the screen, considering 2" of buds will grow above the screen) and train them to the screen bi-daily during the stretching phase.
