If you are opening a bag of soil and it's dry...likely it's been sitting around a while. Lack of moisture kills-off the beneficial bacteria in the soil, but should be ok once re-hydrated. But if that's the case...watch for unwanted bugs.

Give yourself a chance for success. Were I just learning to grow...I'd likely start with the best soil (and nutrients) I could find, and learn while using that. Good products usually produce a consistent result. Buying soil that has been treated like dirt can often lead to inconsistent results. Having said that...I still buy the best I can find locally. (Dr. Q's Filthy Rich Potting Soil, and Fox Farms nutrient 3-pack)

I live in the desert and during the summer, ambient humidity and heat makes it unnecessary to add perlite to the mix. My plants need watering almost daily. But during the cold and sometimes moist winter, I have to add around 20% or so additional perlite to lighten the soil. Otherwise the soil retains too much moisture before it's time to fertilize again per my Fox Farms schedule.

The point being...get to know your soil. Instead of jumping around looking for the perfect mix. Not all mixes are cannabis-ready, and might need adjusting to suit your needs. When in doubt...add perlite. Especially in a moisture-control formula. Different seasons will create different conditions in your garden. <doh>