plus water and nutrients
I have a bagseed strain. My first time growing it I have the same issue. My inexperience in growing mj resulted in not a robust growth. Naturally, I blamed it on the shitty genetic of the unknown strain

. But then, I was determined on accumulating knowledge about growing mj on any style of growing, on any medium. So, my experience and research tells me that everything plays a major role that means your light, your watering, your nutrient, etc. Cannot neglect one without somehow affecting your overall plant growth.
I'm still growing the same bagseed (still scares me to order seeds) but how my seedlings looks like now doesnt resemble how it looks before. Makes me feel like I'm growing a totally different strain. lol