Nutrition
Fertilizer basics: N-P-K and release
Read the three numbers, prefer soil tests over guesswork, and match rate to measured area.
6 min read
The three numbers on a bag are percent nitrogen (N), phosphate (P2O5), and potash (K2O) by weight. A 32-0-4 analysis is high nitrogen with no phosphate and modest potassium. More is not better — excess nitrogen causes surge growth, thatch, and runoff.
Slow-release versus quick-release
Quick-release nitrogen greens turf quickly and can burn if over-applied or applied to wet foliage against the label. Slow-release (polymer or sulfur coated, organic) feeds over weeks and is usually more forgiving. Many consumer bags blend both.
Soil tests beat guesswork
Phosphorus restrictions exist in some states for lawns that already test adequate. Lime and gypsum are not interchangeable: lime raises pH; gypsum supplies calcium and can help sodic or compacted clays without a large pH change. Apply amendments from a test, not a habit.
Convert bag coverage to your measured net square feet, then round bags or bottles up. Do not increase the rate per 1,000 sq ft to “use up the bag.”