nothing wrong with miracle gro, just get the organic potting or seedling mix, might need to add some more perlite to it tho, but its not going to be the cause of your problems, you just need to plant the seed, water it good one time, and you shouldnt have to water it for like atleast 3-4 days, get yourself a moisture meter, they are like 6-7 bucks you can stick it in the soil and just tell when it needs more water instead of guessing.
Theres alot of people who successfully grow using MG soils and have beautiful harvests, its the ones who use soil with nutes in it, and then decide to flood it with more nutes a few weeks into veg and they kill their plants and blame it all on the MG soil