Fertilizer Math: 50-lb Bag, 5,000 sq ft, Drop Spreader Settings

Northern California, 95–100°F summers. 5,000 sq ft lawn. Bought 50-lb "Best" 16-6-8 with Trimec. Bag says 4 lbs/1,000 sq ft (20 lbs total). Spreaders calculators say 40 lbs. Which is right? Safe in heat?

Calculate by Nitrogen, Not Bag Rate

Standard: 1 lb N / 1,000 sq ft per application.
16% N in 50-lb bag = 8 lbs N total → covers 8,000 sq ft.
Your 5,000 sq ft needs 5 lbs N = 31.25 lbs of product.

Bag rate (4 lbs/1,000) = 20 lbs = 3.2 lbs N = 0.64 lbs N/1,000 sq ft—light feeding. Calculator doubling may assume 2 passes or different N target.

Spreader Setting

Check bag for Scotts 1000 settings. If absent, contact Scotts or the store. Calibrate: measure 100 sq ft, catch output, adjust to deliver 3.125 lbs over 5,000 sq ft (0.625 lbs/1,000 sq ft).

Heat Application

Do not fertilize cool-season grass in 95°F+ heat. Wait for fall (Sept–Oct). Warm-season grasses (Bermuda, zoysia) can take summer N. Know your grass type first.

Math > guesswork. Calibrate, then apply at the right season.