Buy Milorganite Slow-Release Nitrogen Fertilizer – 32 lb Bag, Organic-Based 6-4-0

Description

Few lawn feeds can claim a century of continuous use, and milorganite fertilizer earns it by being almost impossible to misuse. It is made from heat-dried microbes, and its gentle 6-4-0 analysis releases nitrogen slowly through soil activity over 8 to 10 weeks. With no salts in the formula, it essentially cannot burn grass, even in summer heat or where spreader passes overlap, and its iron content gives lawns a deep blue-green color that quick synthetic feeds rarely match.

Every application also feeds the soil life that releases the nutrients, so the ground improves along with the grass. This 32 lb bag covers about 2,500 sq ft. Based on manufacturer specifications and decades of owner feedback, it suits families, pet owners and organic-leaning lawns.

Key Features

Organic-Based 6-4-0 from Heat-Dried Microbes

This milorganite fertilizer is made from heat-dried microbes, which gives it a nutrient profile no synthetic bag copies. The analysis reads 6-4-0: modest nitrogen, some phosphorus, and no potassium salts. Because the nitrogen is bound up in organic material, soil microbes release it slowly as they work, which is exactly how grass evolved to feed.

Virtually Zero Burn Risk

The formula contains no salts, and that is why it essentially cannot burn your lawn, even in summer heat, even if you overlap your spreader passes. For anyone who has ever scorched stripes into a yard with a synthetic fertilizer, that forgiveness is the whole reason this product exists.

Iron for Deep Blue-Green Color

Milorganite carries iron, and grass responds to it with a deep blue-green color that nitrogen alone struggles to produce. The effect is a richer, darker lawn rather than a bright, fast flush of growth, and it arrives without the surge-and-fade cycle of quick-release products.

Slow Release over 8 to 10 Weeks

One application feeds for roughly 8 to 10 weeks as soil microbes break the material down. That long, steady release also feeds the soil biology itself, so the lawn and the soil improve together instead of the grass being fed over the top of tired ground.

Product Description

This milorganite fertilizer has fed American lawns for nearly a century, and it keeps appearing at the top of organic fertilizer lists because its strengths are the ones homeowners actually feel: it is safe, it is forgiving, and the color it produces is distinctive. This is the 32 lb bag, which covers about 2,500 sq ft at the standard lawn rate.

Drawn from the manufacturer’s specifications and owner feedback, the consensus is a product that trades speed for certainty. It will not transform a lawn in a weekend. What it does is feed steadily for two months or more, deepen the color, and improve the soil a little with every application, without any risk of the burn patches that ruin synthetic feeding days.

Benefits of Using This Product

The headline benefit is safety. This milorganite fertilizer is safe around kids and pets once it has been watered in, and it is safe for the grass itself in a way no salt-based fertilizer can claim. You can apply it in summer, when lawns are stressed and synthetics are riskiest, and the iron keeps the color deep through the heat.

The second benefit is what happens underground. Because the nutrients release through microbial activity, every application feeds the soil food web as well as the turf. Lawns fed this way tend to hold up better over the years, with thicker growth that crowds out weeds on its own.

Specifications

How to Use

1. Measure your lawn so you know how many bags you need. At about 2,500 sq ft per bag, larger lawns will need several.
2. Set your spreader to the setting printed on the bag for your model, and mow the lawn before applying.
3. Spread in a crisscross pattern, half the product in each direction, for even coverage.
4. Water the lawn lightly after applying. Once it has been watered in, children and pets can use the lawn again.
5. Reapply after roughly 8 to 10 weeks if you want to keep the feeding going through the season.

Why Choose Milorganite?

Choose it when the risk matters more than the speed. New homeowners, parents, pet owners, and anyone feeding in summer heat all land on this milorganite fertilizer for the same reason: it is nearly impossible to get wrong. The iron-driven color is the bonus, and the slow soil building is the long game. Nearly a century on the market, with generations of repeat buyers, is its own kind of evidence.

Frequently Asked Questions

Can Milorganite burn my grass?

Essentially no. It contains no salts, and salt is what scorches grass in a fertilizer burn. Even an accidental double application in one spot will not burn the lawn, which makes it the safest choice for summer feeding and for beginners.

Why is the nitrogen number so low?

The 6 percent nitrogen releases slowly through microbial action over 8 to 10 weeks, so the lawn receives a steady supply rather than a short, sharp dose. The trade-off is coverage: each bag covers about 2,500 sq ft, so big lawns need several bags.

Does it contain phosphorus?

Yes, the analysis includes 4 percent phosphorus. Some states and localities restrict phosphorus applications on lawns, so check your local rules before buying, and skip it if a soil test shows your soil already has plenty.

Is it safe around children and pets?

Yes, once it has been watered in. Water the lawn after spreading, let the granules settle into the turf, and the yard is ready to use again.

Final Verdict

This milorganite fertilizer is the gold standard of organic-based lawn feeding, based on its specifications and decades of owner feedback: it will not burn, it feeds for two months or more, and the iron gives a depth of color synthetics chase and rarely match. Best for: organic-leaning lawns, summer feeding, and families who want zero burn risk. Skip if: your soil does not need phosphorus or local rules restrict it, or you need dramatic green-up within days.

Want to compare it with the other lawn fertilizers before you buy? Read our full guide: 10 Best Lawn Fertilizers for a Greener Yard (2026 Guide)