Milorganite Slow-Release Nitrogen Fertilizer
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Quick Stats
- 6-4-0
- Organic
- 2,500 sq ft
- 8 lbs per 1,000 sq ft
- Yes
- Yes
Verify these figures against the current package before buying or applying.
Pros & Cons
Pros
- Impossible to burn your lawn — the safest fertilizer available
- Slow-release feeds for 8-10 weeks per application
- 2.5% iron provides dark green color without excessive growth
- Organic and safe for kids, pets, and waterways
- Proven since 1926 — iconic brand with cult following
Cons
- Smells for 24-48 hours after application
- Low NPK (6-4-0) means more volume needed per application
- Not a starter fertilizer — use with Scotts Starter for new seed
- Occasionally hard to find due to demand spikes
Catalog pros and cons are not presented as verified product facts. Check the current package and dated source notes before relying on a specific claim.
Fit to verify
Every lawn, honestly. The safest, most forgiving fertilizer for beginners and experienced homeowners alike. — confirm against your own zone, sun, and soil conditions.
Decision Notes
What this page can establish
The catalog identifies Milorganite Slow-Release Nitrogen Fertilizer and links to source notes where available. It does not establish a current seed tag, lot, seller, price, availability, NTEP result, or product performance in your yard.
Verify before choosing
- - Match the current package contents and application rate to the exact SKU.
- - Check cultivar names against relevant trials only when the identity matches.
- - Confirm local species fit with extension guidance and your site conditions.
- - Confirm seller, bag size, price, and availability at checkout.
Other options to compare
These are comparison links, not ranked substitutes or fit recommendations.
Our Notes
Milorganite has a cult following in the lawn care community, and it's completely deserved. This is one of those products where the more you learn about it, the more you respect it.
The basics: Milorganite is made from heat-dried microbes that were used to treat Milwaukee's wastewater. Those microbes consumed nutrients during the treatment process, and the dried result is a slow-release, organic fertilizer with a 6-4-0 NPK ratio plus 2.5% iron. It's been produced since 1926.
The 6-4-0 analysis looks weak compared to synthetic fertilizers (16-4-8 or 24-25-4), but that's the point. Milorganite releases nitrogen slowly over 8-10 weeks as soil microbes break it down. You literally cannot burn your lawn with it. Over-apply by 50%? It'll just feed longer. Apply in the heat of summer? No problem. This safety margin makes it the perfect fertilizer for beginners and anyone who doesn't want to worry about streaking or hot spots.
The iron content gives a noticeable green-up without excessive growth — your lawn looks darker and healthier without needing extra mowing. This 'iron green' is why Milorganite users are so loyal.
The downsides? It smells. Not horrific, but distinctly organic for 24-48 hours after application. And the 6-4-0 means you need to apply more volume (8 lbs per 1,000 sq ft) and more frequently than synthetic alternatives.
We'd recommend Milorganite for everyone as a safe, effective base fertilizer. Layer it 4x per year (spring, early summer, late summer, fall) for a great lawn with zero risk of damage.
Editorial catalog notes — not lab-tested results; verify current label facts.
Where to Buy
Commerce links only. Verify the exact item, seller, package, price, and availability on the retailer page.
Community evidence limit
No synthesized testimonial is presented for this product. Community reports may identify questions or recurring patterns, but they do not establish product quality, value, current package identity, performance, or fit without an attributable source and matching evidence.
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