No superphosphate containing less than 18% available phosphate nor any mixed fertilizer or custom blend , other than a custom blend consisting in part of unacidulated mineral phosphatic materials, in which the sum of the guarantees for the nitrogen, available phosphate , and soluble potash totals less than 20% shall be distributed in this State. Specialty fertilizers are exempt from minimum plant food requirements for mixed fertilizers and custom blends .
505 ILCS 80/10