Use synthetic slow-release fertilizer (24-0-11) for spring and fall maintenance when you want controlled, efficient feeding. Use organic (Milorganite) in summer when heat makes burn risk highest and for building long-term soil biology. Most great lawns use both.
| Attribute | Organic | Synthetic Fertilizer |
|---|---|---|
| Cost per lb of Nitrogen | $2 to $4 | $8 to $15 |
| Speed of Response | 3 to 7 days | 14 to 21 days |
| Burn Risk | Moderate (follow label) | Zero (impossible to burn) |
| Duration of Feeding | 4 to 8 weeks (slow-release) | 6 to 10 weeks (natural release) |
| Soil Biology Impact | Neutral to negative at high rates | Positive (feeds microbes) |
| Pet Safety | Water in, keep off until dry | Safe immediately |
| Environmental Runoff | Higher risk if over-applied | Lower risk (slow release) |
| Precision of Delivery | High (exact NPK control) | Low (variable nutrient content) |
| Availability | Wide (every store) | Good (Milorganite widely stocked) |
| Best Season to Use | Spring, fall, winterizer | Summer (safest burn window) |
Neither is universally better. Synthetic fertilizer delivers faster results at lower cost per pound of nitrogen. Organic fertilizer builds soil health over time, is impossible to burn, and is safer around pets and children immediately after application. Most professional lawn programs use both: synthetic for targeted feeding and organic (Milorganite) as a summer supplement when burn risk is highest.
Better for soil biology and impossible to burn. Worse for cost efficiency and speed of response. Neither is universally better. The most effective lawn programs use synthetic in spring and fall (when precision matters) and organic in summer (when burn risk is highest). Use what fits your goals and budget.
Yes. Milorganite is made from heat-dried microbes (biosolids) from the Milwaukee Metropolitan Sewerage District. It's been OMRI-listed and produced since 1926. The 6-4-0 formula provides slow-release nitrogen and iron. It's the most popular organic lawn fertilizer in the US.
Yes. There's no transition period needed. Many lawn owners apply synthetic in spring and fall for targeted feeding, then switch to Milorganite in summer for safe color. The grass doesn't care about the source of nitrogen. Soil microbes benefit from the organic applications year-round.
Generally safer than synthetic immediately after application because there's no chemical burn risk. Milorganite is non-toxic but dogs are attracted to the smell and may eat it (which can cause mild stomach upset in large quantities). As a precaution, water in any fertilizer before letting pets on the lawn.
Create your account here to access our Membership Content
We have tons of Job information and some valuable information only accessible by our member. Signup here to become a member and access the content.
Already have an account? Login Here
Do not have an account? Signup Here
Copyright © 2026 SunCo Lawns. All Rights Reserved.
