Well, I do see some problems of concern in your leaves.
I get that a lot of people start off thinking it is a weed, and one should be able to put it in some good soil and just water it and all will be good. And to a certain extent this can work. Soil can buffer and sometimes compensate for some shortcomings in a feeding regiment (fertilizer additive) and maybe even compensate, to a certain extent, for watering with water that might be a little too hard and/or alkali in pH, as is the case very often with household tap water.
Also, when growing in soil – you have to be sure the way you are growing will provide enough nutrients the entire life cycle. This is usually done with at least one transplant to a much larger container about midway through the plant’s life-cycle, and the sizes of the containers, and or number of transplants might vary and depend on your desired results and final overall size you want the plant or plants to get.
And so, in your case, I am going to guess, more than only the light being a little too weak and causing some of the stretch and thin look to your plants, it is also likely the plants are having a hard time filling out due them not being able to make good use of the nutrients in the soil because some of the nutrients may becoming unavailable due to a pH nutrient lockout or other problem building up in the soil, maybe nutrient salt build up.
Also, be sure you are not over watering and the roots are getting enough aeration, the roots don’t like it to stay too wet, they like well draining soils, not too unlike a cactus’s roots. Having the roots drowning in too saturated of soil for too long will also cause a pH and nutrient uptake problem at the roots, in and of itself.
I’m not entirely sure what is in b-52, but either way we still need to know what is in the soil and in your water to know why your plant’s leaves are looking stunted, twisted and a little burnt.
It is worthwhile getting the tools to be able to know the answers to the questions you were not able to fill out.
Check out this blog by Robert on why checking your soil regularly is a good idea:
And for measuring the humidity:
http://shop.ilovegrowingmarijuana.com/collections/grow-equipment/products/gro1-weather-station