If you were to ask a worm, Miracle grow and any chemical fertilizers are the devil!. Worms are the work horses of the garden. The processes of worms living turn old plant material into compost and worm casings that enrich the soil, and fight off and prevent plant diseases. Worms themselves also give off materials that are fungacides and materials that help the enchange and growth of nutrients and water from the plant roots.
Ever get salt on a cut or a cracked lip? Hurts don't it. Worms feel the same way. They are softbodied animals and the salts in any fake, or Miracle grow product feel like someone is pouring acid on them. THey take off and your gardens fertilitiy suffers. In additon, without the worms, diseases increase inlcuding bacterial wilts and other soil born diseases that have no real cure. So you can ruin your entire plot by destroying natures balance.
Even if the worms are not severely affected right away, other problems result. Ever seen a kid or adult that eats too much sugar. Sooner or later they get sick. The articifically high nitrogen content attracts BUGS just like sugar attracts bacteria to rot your teeth. So now you have to pesticides and disease killers to keep your plants alive which kills off more natural predators so you ahve to keep spraying.
Every rain washes your fertilizerand pesticide into the human water suppy where you and your kids and all the fishes in the world get to drink it! This causes the algea to bloom in lakes so the fishes die, and of course humans are not supposed to be drinking fertilizers. There is No way to get it out of the water!
Use an organic fertilizer. It feeds and attracts plants and worms. It is long lasting. It helps discourage bugs and disease, and it
doesn't wash away with a rain. You will not end up feeding it to the whole world either.