Master gardener Larry Hall out in Minnesota recommends mixing up your own potting soil, and saving plenty of money!
Please note: Miracle Grow is mentioned in this video as a positive product (although not used in the featured recipe). Nextworldtv does not endorse the use of Miracle Grow, or any Scott's product as it's parent company is Monsanto.
Use this instead and skip the Miracle Grow!
Here is his recipe:
2 five gallon buckets full peat moss
1 five gallon bucket well rotted horse manure or compost or worm castings
1 and 1/2 cup garden lime
1 large coffee can full of perlite
1 handful of epsom salts