Here's something that I copied quite a while ago from a Rodale
publication – about Miracle grow.
Carol M

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Miracle-Gro is a synthetic fertilizer that contains ammonium phosphate, 
ammonia sulfate, and several other chemicals that can be toxic to your 
soil and plants.

It is prohibited from use in certified-organic farming. Here's what 
soil expert Robert Parnes, Ph.D., says in his book Fertile 
Soil: "[Ammonium fertilizer] acidifies the soil, and thus it is 
probably more harmful to soil organisms than any other nitrogen 
fertilizer . . . . The application has to be timed carefully and 
placed properly to avoid burning the leaves and roots . . . . In 
addition, ammonium tends to inhibit the release of . . . 
potassium . . . Ammonium fertilizers are deliberately manufactured to 
be spread at high application rates in order to obtain maximum yields 
with no regard to adverse effects on the soil. Probably nowhere is 
the conflict between the mass production of food to feed the world 
and the preservation of the soil more obvious
than in the confrontation over the use of either ammonium fertilizers 
or liquid ammonia."

And there's more: long-term studies at the University of Wisconsin 
have shown that acidic chemical fertilizers are causing serious, 
permanent damage to our soils. Usually these fertilizers are also 
highly soluble, so they leach away and pollute our water systems, 
too. Soil fertility authority Garn Wallace, Ph.D., of Wallace 
Laboratories in El Segundo, California, points out that Miracle-Gro 
contains muriate of potash, which contains excess chlorine that will 
burn plants and inhibit the uptake of nitrogen. Dr. Wallace also 
warns that products such as Miracle-Gro often contain unsafe levels 
of zinc and copper that will be toxic to soil life.

And if all that's not enough to convince you to avoid this stuff,
consider this: you have to mix Miracle-Gro with water and apply it 
every "7 to 14 days." If you opt to fertilize organically, on the 
other hand, all you have to do is mix a 1/2-inch layer of grass 
clippings into your beds before each crop. As the grass decomposes, 
it will improve your soil's texture and stimulate microbial life and 
help prevent disease, all the while releasing plenty of nutrients to feed your 
plants. 

(For full details on organic fertilizers, see "How to 
Fertilize Your Garden," Organic Gardening, July/August 2000.)

Soil being everything, soil must contain Life in the form of 
microscopic bacteria and other weird looking life forms. Use of 
shortcuts is never recommended and this stuff, despite millions of 
dollars worth of marketing, can be nasty for sustainable organic gardening.

<from Rodale>

