Not sure what kind of education you have in hortuculture or anything, but good fertile soil will be very dark, crumbly, look just rich. Soil can be sandy, clayish or a mix of any. Luckily where i come fertile soil is very accessible, I still add some MG though when I first plant them in the ground. This way the roots have some space because the soil could become compact.

Plus, I dont have to worry about nutes for a while and once the roots start to take off you will see growth accelerate after 2 weeks. Digging up your plants was not a good idea cause you just caused more stress and they were just getting adjusted to the ground. Now they have to start all over again.