It's just a moisture retentive soil mixture w/Osmocote in it, according to Scotts.
From a week ago, in reply to an e-mail I sent them.
"Miracle-Gro Moisture Control Potting Mix feeds for 3 months with Osmocote. Osmocote works on the principle of osmosis, which is how the product gets its name. Osmocote prills absorb moisture from the soil, causing them to swell into plump capsules of liquefied plant food. The nutrients are then slowly released through the prill's special coating to the plant's root zone through osmosis. This constant supply promotes beautiful plants. And since the nutrients are encapsulated, they will not wash away - no matter how much it rains or how often you water.
After three months, you can begin feeding plants on a regular basis with Miracle-Gro All Purpose Plant Food. We suggest you repot plant every 9 to 12 months.
Miracle-Gro is a water soluble food which is specifically formulated for use with all varieties of plants grown under normal cultural methods. Miracle-Gro contains the primary plant nutrients of nitrogen, phosphoric acid and potash, and six minor elements. The specific blend of these nutrients is designed to promote vigorous plant growth and vegetable and flower production.
Miracle-Gro All Purpose Plant Food contains the following micronutrients:
Boron 0.02 %
Copper 0.07 %
Iron 0.15 %
Manganese 0.05 %
Molybdenun 0.0005%
Zinc 0.06 %
Boron - disease resistance
Copper - in some enzyme systems
Iron - required for chlorophyll
Manganese - component of chlorophyll productions
Molybdenum - nitrate reduction
Zinc - structure and function of nucleic acids"