Your container plants will need a regular feeding schedule as nutrients will wash out of the containers. Weekly is a common recommendation. every other week should work depending on the size of your containers.

The fertilizer is your choice. Personally I don't care for MG products and firmly believe there are much better products on the market. They contain too much salt and are "overdose" ferts IMO but some folks swear by it so your choice. The search will pull up lots of discussions here on fertilizing/feeding plants if you want to read through them.

In-ground plants are often fed on a 6 week cycle - at planting, after first fruit set, 6 weeks later, etc. through out the season. That is what our Master Gardener program here teaches. I think the frequency all depends on the quality of your soil bed, how well it was amended prior to planting, and the type of fertilizer you use.

In other words, IMO feeding the in-ground bed by the 6 week calendar often leads to OVER-fertilization which wastes $$, stresses plants, and contaminates ground water. So you have to really know the quality and nutrient levels of your garden.

But as a general rule, average soil and using liquids will require more frequent feedings than using a granular fertilizer will or than a well amended bed will.

Hope this helps.

Dave