A year ago, I wrote in this column about the importance of correcting acidic soils to make sure our forages grow green and fast in Tennessee pastures. However, in the last few months, I have been receiving several calls about “liquid lime” or “liquid calcium,” as the product is registered.

For example, last month I received two soil test reports from a producer in Morgan County, TN. He tested his soil pH in October 2025 and found a soil pH of 5.99, with a recommendation to apply 1.5 tons of lime per acre. Instead of using ag lime, he was convinced to use liquid lime, which is NOT recommended. However, very wisely, he decided to test the soil again after using the product. In February 2026, his soil test report came back with a pH of 5.87, showing that his pasture was still in need of correction.

We could come up with hundreds of excuses for why the soil pH did not increase, blaming the environment, timing, sampling methods, lab analysis procedures, among others. The fact is that the product was applied and the soil pH was not raised. This is no surprise, as well-respected land-grant universities have also tested liquid products claiming to change soil pH and found no results.

At the University of Kentucky, the product was tested on 16 farms where four treatments were applied side by side: (1) a control with no application, (2) liquid lime, (3) pelleted lime, and (4) ag lime. They measured soil pH right before application and again 3, 6, and 12 months after application. Soil pH started to increase after 3 months for ag lime and pelleted lime, and changes continued to be measured up to 12 months, as expected. The control and liquid lime treatments remained with the same low soil pH measured at the beginning of the 16-farm trial. No changes in soil pH were found.

As I mentioned in this column before, low soil pH reduces the availability of nutrients to plants. However, if you can keep your pasture soil pH between 6.0 and 7.0, nutrients will not be held too tightly to soil particles, making plant uptake much easier. For that reason, the recommended range for common Tennessee forages like tall fescue, orchardgrass, crabgrass, and sudangrass is a soil pH between 6 and 7. If you are growing legumes such as alfalfa or clovers, keeping the pH above 6.5 is even more important, as they are more sensitive to acidic environments.

One thing to remember: changing soil pH takes time. Lime needs moisture (rainfall) and from three months to a year to fully react in the soil. If your soil test shows low pH, apply ag lime (NOT liquid products) as soon as possible. If you are planning to renovate a pasture this fall—which is the best time to plant cool-season forages—applying ag lime now will improve soil conditions in time for seeding. By September, soil pH will have increased enough to create a better environment for seedling establishment.

My grandpa used to say, “If it seems too good to be true, it probably is.” So please take a soil sample, and if the soil pH is low, ag lime is still the only proven way to correct soil acidity. Don’t hesitate to call your Extension office—we have one in every county.