How long do soil amendments take to work?
Written by
Kiana Okafor
Reviewed by
Prof. Martin Thorne, Ph.D.The timeline to plan for soil amendments, including lime or sulfur, is closely tied to pH testing the soil. Elemental sulfur is the fastest to work, dropping soil pH up to 0.5 pH units in 3 weeks if soil moisture is maintained to optimal levels. Agricultural lime takes longer, typically 3-6 months before the full change is achieved. A pasture of a client that was too acidic had to have two applications of lime over 8 months before the pH stabilized to 6.8.
Fast-Acting Solutions
- Elemental sulfur: 2-4 weeks (ideal for urgent corrections)
- Aluminum sulfate: 1-3 weeks (caution: root burn risk)
- Vinegar drench: 48-hour pH drop (temporary fix)
Slow-Release Options
- Agricultural lime: 2-6 months (long-term stability)
- Wood ash: 3-8 weeks (weather-dependent)
- Crushed eggshells: 6-12 months (mild alkaline shift)
Regional soils are highly influential. Limestone bedrock areas resist pH reductions and on a farm in Missouri that was dealing with a 7.8 pH clay soil, I used doubled sulfur rates. Volcanic soils in the Oregon coast range acidify quickly, so I check lime to pH twice a year. Don't forget, that I always test the subsoil and deep layers, those profile materials will ruin surface amendments.
Safety equipment saves lives. Aluminum sulfate dust necessitates N95 masks. I learned this from a persistent cough in a gardener. Lime, I utilize goggles when wind may pose a danger when applying it. I also get the clients ready with gloves adjusted for pH levels and rinsing stations available in emergencies. Your safety is not a negotiable issue.
Read the full article: Soil pH Testing: 7 Essential Steps for Accurate Results
