many use m.g. for tomatoes during the veg and schultz' bloom or super bloom for flowering. i use it too at times and have also used fox farms and other similarly specialized ferts...i've found with care m.g. works just as well as the more expensive fox farms-type products (i am speaking about soil only). same goes for bloom and super bloom. but i always cut the directions in half and never give more than once every couple weeks. others use a stronger strength and give more often...you'll have to find what works best for your area and conditions. experiment on different plants of same strain and you'll quickly find what's best. it doesn't take long for a reaction when too much of anything gets added which is why i suggest going slow and working up to find optimum level.

but there is no need to use different ferts for veg or flowering...one of each is fine.