I have no idea where to ask this so i just chose this forum but i have a couple questions about fertilizing and fertilizers.

1- I bought some Miracle Grow Water Soluble 15-30-15 and im wondering if this is a safe formula to use for all my fertilizing needs, im growing a variety of plants and don't want to buy 2,3,4 or 5 different ferts for each type. Im growing annuals in the grow and container and perennials, veggies, peppers. So im just wondering if 15-30-15 would be good enough for all of these or would it be bad for some?

2- The pail or fert i bought doesn't list an expiration date, does it expire?

3- If i make 1 gallon of the fert up and only use half of it can i store the rest for a couple of weeks until i use it again or does it need to be used as made?

Thanks i hope someone can help me :).