Magruder Fertilizer Proficiency Testing Program

The Magruder program is a proficiency testing program for fertilizers. Each subscribing laboratory receives one or two samples each month. The samples contain varying levels of plant nutrients as well as trace metal contaminants.

2025 SUBSCRIPTIONS NOW ACCEPTED

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 2025.