Choosing Lawn Fertilizer: Liquid vs. Granular, Cost vs. Convenience

When a gardener asked about the best fertilizer form for bermudagrass – liquid or granular – I realized the answer comes down to basic math and the "convenience versus cost" tradeoff we face in many decisions.

The Big Picture

All lawns need extra nutrients during their growing season. Centipede needs little; fescue and bermuda need more. Form (granular vs. liquid) doesn't matter to the grass – but it matters to your wallet and schedule.

Scientists recommend 1 pound of actual nitrogen per 1,000 sq ft monthly for bermudagrass during growing season. "Actual nitrogen" is the concentrated nitrogen chemical (ammonium nitrate, urea, etc.) you apply. A 10-10-10 bag is only 30% nutrients; the first number indicates nitrogen percentage.

Calculating Actual Nitrogen

Formula: Divide the first fertilizer number into 100. The result = pounds of that fertilizer needed to supply 1 lb actual nitrogen per 1,000 sq ft.

• 29-3-4: 100 ÷ 29 ≈ 3.5 lbs
• 16-4-8: 100 ÷ 16 = 6.25 lbs
• 15-30-15 (liquid): 100 ÷ 15 ≈ 6.66 lbs

The Pocketbook Question

At a garden center, I found:

• 29-3-4 (slow-release, 2-month feed): $1.67 per lb actual nitrogen
• 16-4-8 (monthly application): $0.93 per lb actual nitrogen
• 15-30-15 liquid (every 2-4 weeks): $17.76 per lb actual nitrogen

The huge discrepancy? Convenience. Slow-release products cost more but save time (8-week intervals). Liquid feeds absorb faster (greens up in days) and require no spreader storage, but need frequent application with a handheld sprayer.

Like restaurant dining vs. home cooking: you pay for convenience. Whether choosing fertilizer or dinner, the "convenience versus cost" calculation is a life skill worth mastering.