6-4-0 Fertilizer
OrganicAlso known as: Milorganite and similar biosolids
6-4-0 is 6% nitrogen, 4% phosphate and 0% potash by weight. To apply 1 lb of nitrogen per 1,000 sq ft, spread 16.7 lbs of product per 1,000 sq ft; a 50-lb bag covers about 3,000 sq ft at that rate.
What 6-4-0 Means
Nitrogen (N)
6%
3 lb per bag
Green color and growth
Phosphate (P₂O₅)
4%
2 lb per bag
Root growth, new seedlings
Potash (K₂O)
0%
0 lb per bag
Stress, drought and cold tolerance
Pounds shown are per 50-lb bag. The N:P:K ratio simplifies to 3:2:0. The remainder of the bag is carrier, filler, and secondary nutrients.
How Much 6-4-0 to Apply
Lawn feeding is measured in pounds of nutrient per 1,000 sq ft. Here's how much product hits each common target.
| Target | Product / 1,000 sq ft | Per acre | 50-lb bag covers | Delivers (N-P-K lb) |
|---|---|---|---|---|
| 0.25 lb N | 4.17 lb | 182 lb | 12,000 sq ft | 0.25-0.17-0 |
| 0.5 lb N | 8.33 lb | 363 lb | 6,000 sq ft | 0.5-0.33-0 |
| 0.75 lb N | 12.5 lb | 545 lb | 4,000 sq ft | 0.75-0.5-0 |
| 1 lb N | 16.7 lb | 726 lb | 3,000 sq ft | 1-0.67-0 |
What It's For
A low-analysis organic nitrogen (Milorganite is the best-known). It releases slowly as soil microbes break it down, won't burn, and adds iron.
When to Use It
Spring through fall. Microbial release slows in cold soil, so it does the most once soil is above about 55°F.
Before You Spread It
- Low analysis means a lot of product: about 17 lbs per 1,000 sq ft for 1 lb N. Bags go quickly on large lawns.
- Contains phosphorus, which some states restrict on established lawns.
6-4-0 Products in Our Catalog
6-4-0 Calculator
Enter your lawn size to get the total amount, or change the analysis to check a different bag.
Spread 16.67 lb per 1,000 sq ft, 83.33 lb for 5,000 sq ft (1.67 bags).
Delivers 1 lb N, 0.67 lb P₂O₅ and 0 lb K₂O per 1,000 sq ft. Never exceed the label rate.
Common Questions
How much 6-4-0 per 1,000 sq ft?
To deliver 1 lb of nitrogen per 1,000 sq ft, apply 16.7 lbs of 6-4-0 per 1,000 sq ft, or about 726 lbs per acre. Many applications use half that or less, and the product label rate always comes first.
What is 6-4-0 fertilizer used for?
A low-analysis organic nitrogen (Milorganite is the best-known). It releases slowly as soil microbes break it down, won't burn, and adds iron.
When should I apply 6-4-0?
Spring through fall. Microbial release slows in cold soil, so it does the most once soil is above about 55°F.
What do the numbers 6-4-0 mean?
They're the percentages by weight of nitrogen (N), phosphate (P₂O₅) and potash (K₂O). A 50-lb bag of 6-4-0 contains 3 lbs of nitrogen, 2 lbs of phosphate and 0 lbs of potash; the rest is carrier and other ingredients.
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