Like all items you specify there are wide differences between products that are classified as "Mycorrhizal" products.  You must be specific and specify the quantity of active organisms or the lowest quality product possible will be used by the landscape contractor that is doing the job.  There are competitive products out there in which you would need 20 times as much of in order to equal our products, and yet these products are called "Mycorrhizal" products.  Most do not include a bacteria package, especially important in soils that have been moved around or stockpiled.  Few include Trichoderma fungi which can be very important to protect the roots from negative fungi that are in all soils and are especially problematic in compacted construction sites, etc.  These products, although lower in cost, are really very expensive because they do very little in the landscape.

Do Not use a general specification.  If you want good results, require good ingredients in amounts that will give your client all of benefits he can hope for.  Remember if you did not give specific specifications for parking lot lighting a torch stuck in the ground would meet an open spec.   Be specific, get results.  Be a generalist, get hooked...

To illustrate this point look at a competitive analysis between products. 

For technical questions contact manufacturer at:

Horticultural Alliance, Inc.
1550 66th Ave. Dr. East
Sarasota, FL 34243
Tel: 800-628-6373 (US only), 941-739-9121
Fax: 888-483-4200 (US only), 941-752-1890
Website: http://www.horticulturalalliance.com