Skip to main content

Thornton Laboratories Testing & Inspection Services, Inc.

Leader in Fertilizer Analytical Services

Microbiological Testing
Fertilizer Testing
About Us
Contact Us
Site Map
Member Login


With consistent growth since its founding in Tampa, Florida in 1922, Thornton Laboratories, has continuously expanded its laboratory capabilities and services. Continued involvement in new techniques have enabled Thornton to continue meeting the demands of the Fertilizer and Agricultural community. In 1972, the company entered the international trade market and, brings surveying and inspection services to an international clientele on a worldwide basis.



Thornton Laboratories

Testing & Inspection Services, Inc.

(813) 223-9702 Main
(813) 223-9332 Fax
1145 E. Cass St.
Tampa, FL 33602


Thornton Laboratories' staff includes experienced professional chemists, technicians, microbiologists, surveyors and samplers, as well as a full supporting administrative staff. A computerized Laboratory Information Management System (LIMS) provides sample tracking, data storage and retrieval.


Through its expertise and experience in sampling and analysis of fertilizer,agronomic materials and phosphate ores, Thornton Laboratories provides professional counsel in problems relating to quality assurance, method evaluations and sampling protocols. Investigations of matters involving government regulations or trade organizations are strictly unbiased.

Facilities and Equipment

The company is headquartered in Tampa, Florida.

The laboratories are equipped with modern, comprehensive analytical instrumentation, and expertise in classical wet chemical techniques is maintained.




AFPC - Association of Fertilizer & Phosphate Chemists

AOAC - Association of Official Analytical Chemists

AAPFCO / Magruder

TFI - The Fertilizer Institute

Quality Control

Accuracy is assured with in-house quality control programs as well as by performance monitoring through participation in industry and government sponsored performance evaluation studies - AFPC, Magruder, AOAC- LPTP (Microbiology).