Welcome Mex
These plants are in the ground not pots correct?
You can use MG.
Make sure to start out 1/2 of recomended dose.
Mix nutes with water and pour the mix in a circle around the plant.
I would say atleast 4-5" away from the plants.
Depending on the soil you may not even need nutes.
What is you general location? (part of the world for climate sake)
I would read this whole thread by Beaner If I were you.
Beaner has toooo much time on his hands!
Less is more with nutes.
Happy growing.