Magruder Fertilizer Proficiency Testing Program
The Magruder program is a proficiency testing program for fertilizers. The samples contain varying levels of plant nutrients as well as trace metal contaminants.
2026 SUBSCRIPTIONS NOW ACCEPTED
View the Step-by-Step Payment Instructions
Available schemes are:
- Regular Scheme: 12 samples ($360 plus shipping)
- N Scheme: 3 samples ($130 with Regular Scheme; $200 alone; plus shipping)
- P Scheme: 3 samples ($130 with Regular Scheme; $200 alone; plus shipping)
- K Scheme: 3 samples ($130 with Regular Scheme; $200 alone; plus shipping)
Partial payments are not accepted. If you join a Scheme after a round has been shipped, all past samples will be sent after payment is received. Your lab will not receive reports for completed rounds.
View the current sample schedule for 2026.