Here's some tips:
1) I see that your grow media is "soil" and you have cal-mag listed as one of your nutrients. Hopefully at this young seedling stage, you have not used it yet. Hold onto it for now. You may very well need it later once you start flowering. Too often, a grower will reach for cal-mag during the vegetative cycle of plant growth where what they really need is a boost of magnesium. (This is especially true under LED lights) Many people will ask what's wrong with using cal-mag since it contains magnesium? The problem with it is calcium in excess causes lock-out, especially of magnesium. There's a very easy and cost effective way around this .... use unscented epsom salts at 1 teaspoon per gallon of feed during veg. Then once in flower, switch to cal-mag if needed.
2) Soil pH should be between 6.0-7.0 with 6.5 being the sweet spot. Both lower and higher out of range pH will make certain nutrients unavailable for plant uptake. This is critical since once your plants are planted in it, it's hard to correct. I use either Roots Organic "Original" potting soil mix or Fox Farm's "Ocean Forrest" because they are easy to find at a decent price in my area. What's most important when choosing your mix is that it starts in the right pH range. Most top brands of mixes designed for cannabis will be in this pH range out of the bag.
3) Don't over-look environmental controls ... daytime and night time temps/humidity control are essential if you want to consistently produce high grade cannabis. I like the UIS system from AC Infinity ... once you get through the learning curve on the app set-up, it makes managing the environment pretty simple.