I think that the first six months of an SHTF gardening would be out of the question since the garden would be seen by many that would want to take it all.
You may find some things that can grow in side the home like bean sprouts. I grow mung beans in five day inside the house. They can be added to rice which would add protein. This is just one of many that can grow inside the house for the first six months to a year.
You need to save water and can foods for your family for a year.