Organic Maintenance Fertilizer 18-1-8+fe

For most lawns, 2–3 applications per growing season is ideal. Cool-season grasses (fescue, bluegrass, ryegrass) benefit from a spring and fall application, with an optional light summer feeding. Warm-season grasses (bermuda, buffalo, zoysia) do best with applications every 8–12 weeks from spring green-up through late summer. Because 85% of the nitrogen is slow-release, each application feeds for 12–16 weeks—so you need fewer trips with the spreader compared to synthetic fertilizers.

The organic compost base makes this fertilizer much safer than many synthetic options. However, we recommend keeping pets and children off the lawn until the granules are watered in and the lawn has dried—typically a few hours after irrigation. The iron component is the main concern: if a dog eats a large amount of granules directly, it could cause stomach upset. Once watered into the soil, the product poses minimal risk. Always store bags in a secure location away from pets.

For brand-new seedlings, we recommend starting with our Organic Seed Starter Fertilizer 4-6-4 instead. Its higher phosphorus content supports root development during the critical establishment phase. Once your new grass has been mowed 2–3 times (about 6–8 weeks after germination), transition to 18-1-8+Fe for ongoing maintenance. The slow-release formula is gentle enough for young turf but delivers the higher nitrogen that established lawns need for thick, green growth.

Yes—the iron (Fe) in this product can leave rust-colored stains on concrete, stone pavers, and other hard surfaces. The fix is simple: sweep or blow all granules off hard surfaces immediately after applying, before watering. If granules sit on concrete and get wet, the iron dissolves and stains. The stains are cosmetic and usually fade over weeks of weathering, but prevention is much easier. Avoid applying near white stone, light pavers, or pool decks.

Suståne 18-1-8+Fe has a significantly higher nitrogen content than Milorganite (6-4-0) or most organic-only fertilizers. That means you apply less product per feeding and get stronger results. The “organic-based” formula combines the soil-health benefits of compost with the performance of controlled-release technology—giving you the best of both worlds. The added iron is another advantage for lawn color that many competitors lack.

At the standard maintenance rate of 5.5 lbs per 1,000 sq ft, one 50 lb bag covers approximately 9,000 sq ft. At a heavier rate of 10 lbs per 1,000 sq ft (for fall feeding on cool-season lawns), one bag covers about 5,000 sq ft. For warm-season lawns at the lighter 2.75 lb rate, one bag can cover up to 18,000 sq ft. Check the rate that matches your grass type and season.