I've been at this a long time. I grew my first cannabis plant around four decades ago and was indoctrinated into the world of gardening almost fifty years ago. I know my way around the school yard
Both those places have good stuff but the prices are much different so it's best to check those before buying. For example a 40lb bag of alfalfa meal is $99 at greenwaybiotech but the same exact bag is $70 at buildasoil. Fortunately here in Portland there is a place called Naomi's organic farm supply that sells the same stuff and I bought the exact same bag of the Pro-Pell-It alfalfa for under $50. I don't remember the exact price but they also have kelp, crustacean meal, and everything else in 40 - 50lb bags really cheap. Which is good because I'm a cheap mofo. My slogan is Cheap and Proud.