Label Interpretation and Calculations Flashcards

A fertilizer bag lists the guaranteed analysis as 10-5-8. What does the middle number (5) represent?

Answer: Available phosphate (P2O5) percentage

The middle number in the N-P-K analysis always represents available phosphate expressed as P2O5.

A fertilizer label states 'Apply at 4 lbs per 1,000 sq ft.' How many pounds are needed for a 15,000 sq ft lawn?

Answer: 60 lbs

4 lbs × (15,000 ÷ 1,000) = 4 × 15 = 60 lbs.

What does the term 'slow-release nitrogen' on a fertilizer label indicate?

Answer: Nitrogen is converted by soil microbes or water over time

Slow-release nitrogen is formulated to break down gradually via microbial activity or hydrolysis, extending nutrient availability.

A 50 lb bag of 20-0-10 fertilizer is applied to 5,000 sq ft. How many pounds of actual potash (K2O) are applied?

Answer: 5 lbs

50 lbs × 10% K2O = 5 lbs of actual potash applied.

Which section of a fertilizer label is legally required to list nutrient guarantees?

Answer: Guaranteed analysis

The 'Guaranteed Analysis' section is the legally mandated portion listing minimum nutrient percentages.

A spreader is calibrated to deliver 3.5 lbs of product per 1,000 sq ft. What total product is needed for an 8,500 sq ft area?

Answer: 29.75 lbs

3.5 lbs × (8,500 ÷ 1,000) = 3.5 × 8.5 = 29.75 lbs.

A fertilizer label lists 'Derived from: urea, muriate of potash.' What does this statement indicate?

Answer: The sources of nutrients in the product

The 'Derived from' statement identifies the specific ingredient sources that provide the guaranteed nutrients.