thecomp said:
The food instructions say 10-14 days, but is this too often to feed or are the manufacturers trying to move more product?
The product is very fast release, and the volume you apply is very low, so the application rate is not too high for what I assume you're trying to do, get fast growth.
What might be a better approach, is to use composted cow manure. It comes in 40 pound bags for a couple bucks. The advantage is that you get similar fertilizer, in a slow release product, and it adds organic matter to the soil.
One bag covers an area about 10 x 10 feet. You're putting down a large volume, compared to the chemical fertilizer, but it has a much lower percentage of nutrients, but in the end you basically end up with the similar amounts.
Then after you apply the compost, and maybe even work it in with a pitch fork a little, you can cover the area with a thin layer of decorative wood chips. This will help keep the soil moist, moderate soil temperatures, look nice, and in time will break down and become compost itself.
Adding a bit more compost and/or a thin layer of chips each year will keep it looking good and create a layer of organic matter at the surface that will be similar to a healthy forest floor. The chip area can grow larger as the trees spread, to keep away competitive plants, like grass.
The Miracle Grow is good when you want fast response, so for flowers, shrubs, and short lived plants that you want to grow fast, spray away. Accelerating tree growth can be tricky though. Lush green growth is more attractive to insects, and long growth increments on an Arb, can be problematic come winter, with a snow load.
When you buy fertilizers, you're really buying Nitrogen. All the other stuff is just window dressing. To figure out how much you are paying for the Nitrogen, take the weight of the product and multiply it by the percentage of Nitrogen. This number tells you how many pounds of actual nitrogen you're buying. I think you'll find Miracle Grow is quite expensive, as well as Blue's magic liquid, not that either product is bad.