Milorganite vs Synthetic Fertilizer: Organic vs Fast-Release Feeding
Product specs below are estimates for planning purposes. Always verify against the current product label and your supplier's current listing before buying.
Milorganite 6-4-0
Milorganite
PGF Complete 16-4-8
The Andersons
| Active ingredient | Nitrogen 6% (slow-release, biosolid-derived), Phosphorus 4%, Iron 2.5% | Nitrogen 16% (slow-release, with humic acid), Phosphorus 4%, Potassium 8% |
|---|---|---|
| Coverage rate | One 32 lb bag covers ~2,500 sq ft at standard rate | One 40 lb bag covers ~10,000 sq ft |
| Best for | Iron-driven greening without a growth surge, very low burn risk, organic programs | Higher-efficiency nitrogen delivery per dollar, fewer applications needed |
| Application method | Granular, apply with broadcast or rotary spreader | Granular, apply with broadcast or rotary spreader |
| Applicable zones | cool, warm, transition | cool, warm, transition |
| Where to find | SiteOne, DoMyOwn.com, Solutions Pest and Lawn | SiteOne, DoMyOwn.com |
| Grass Type Compatibility | ✓ Safe for all grass types | ✓ Safe for all grass types |
Which Should You Choose?
Choose Milorganite when you want the safest possible product around kids, pets, and waterways, plus iron greening without excess top growth, and accept a higher cost per 1,000 sq ft and more frequent bag changes. Choose a synthetic like PGF Complete when you want more total nitrogen per dollar and faster visible results. Many professional programs use both: synthetic for the bulk of the season, Milorganite for a late-season iron pass.
Get a personalized plan that includes the right product for your lawn.
Build My Plan