Confusing Tennessee Soil Test: High P, High K, pH 7.4 — What Now?

Raised beds: 50% topsoil, 50% mushroom compost. TN Ag test says "tests don't work with organic material," pH 7.4, P very high (120+), K high (245). Suggested 15-15-15, then manager said no. Suggested ammonium nitrate — can't find. Growing potatoes, tomatoes, corn, squash, pumpkins.

Decoding the Confusion

• "Tests don't work with organic material" → likely means: wait for compost to mineralize before testing for plant-available nutrients. Valid point.
• pH 7.4 is fine — most crops thrive 6.5–7.5.
• NO 15-15-15 — excess P and K already.
• NO ammonium nitrate (33.5-0-0) — half nitrate leaches instantly, pollutes water.

What Crops Need

• Corn: optimal N-P-K ratio 1.25-0.5-1.5.
• Potatoes/tomatoes: prefer nitrate nitrogen.
• Red clover interseed boosts N naturally.
• Excess P blocks Cu/Zn; excess K blocks Mg/Mn/Zn/Fe.
• Boosting N can rebalance — but precisely.

Next Step

List exact crops → I'll give specific N strategy. Mushroom compost continues releasing — factor that in.