You can apply lime and fertilizer to your lawn at the same time, but if your soil is too acidic, it won’t matter how much fertilizer you put down. The grass simply can’t use those nutrients until you correct the pH.
Lime doesn’t feed your grass directly, but it changes the soil environment so fertilizer can actually do its job. If the soil is too acidic, nutrients like nitrogen and phosphorus get “locked up,” and your lawn won’t see the benefits of fertilization. Adding lime raises the pH gradually, creating a balanced soil where grass roots can take up the nutrients they need.
Just know that one mistake can set your lawn back months, so if you’re worried about over-application, or simply don’t want to risk injuring your lawn, consider using a professional fertilization service.
How lime and fertilizer work for your lawn
Fertilizer is plant food; it provides nutrients that grass needs to grow. Lawn fertilizers supply three major nutrients – nitrogen for green growth, phosphorus for root development and energy use, and potassium for disease resistance and overall hardiness. These nutrients are listed on fertilizer bags as N-P-K numbers.
Lime isn’t a fertilizer; it’s a soil amendment that raises the soil pH (reduces soil acidity) by adding calcium and magnesium. Turf generally does best in slightly acidic to neutral soil (around 6.0 to 7.0). When the pH is too low, nutrients get tied up and grass struggles to use them.
“If your soil pH is too low (below 5.5), most plants will not grow well no matter how much fertilizer you add,” explains Charlotte Glen, master gardener, NC State University Extension.
But lime is not always needed. Alison O’Connor, extension professor of horticulture with Colorado State University Extension, cautions that there are places, such as Colorado, where soils already contain plenty of natural lime.
“Since Colorado soils have a lot of free lime, adding more is generally not one of our recommendations,” she explains. “This is generally done in Eastern climates that tend to have more weathered, acidic soils.”
In short, fertilizer feeds your grass; lime balances the soil so that the feed works. Because every yard is different, a soil test tells you if lime is needed, how much to apply, and the nutrients your lawn actually lacks. It also prevents over-liming that can create new problems.
Read more:
- What is N-P-K? A Guide to Understanding Fertilizer Ratios
- Benefits of Lime for Your Lawn
- How to Soil Test Your Lawn
Benefits of simultaneous application
Applying lime and fertilizer at the same time can have some advantages:
- Convenience: The biggest benefit is saving time and labor. Applying lime and fertilizer together means fewer trips across your lawn; one pass with the spreader takes care of both.
- Dual action: Your lawn gets nutrients from the fertilizer right away, while the lime begins its work adjusting soil pH.
- Single weather window: You need to apply lawn fertilizer when some rain is expected, but not a downpour that would cause runoff. Lime, similarly, should be watered in after application. Combining applications allows you to capitalize on one ideal day of mild rain or watering.
- Soil Improvement: Combining lime with your fertilization schedule can jump-start soil correction.
Read more: Best Fertilizer Spreaders
Drawbacks of simultaneous application
On the other hand, there are some drawbacks and potential inefficiencies when you apply lime and fertilizer at the same time:
- Nutrient loss: One drawback is a chemical interaction that can occur with ammonium-based fertilizers. According to Rocky Lemus, professor and researcher at the Mississippi State University Extension, applying lime at the same time as these fertilizers can cause some of the nitrogen to convert to ammonia gas and be lost to the air. In practical terms, you might lose a portion of the nitrogen you paid for.
- Phosphorus tie-up: Calcium in lime can bind with phosphorus from fertilizer, forming insoluble compounds, making some of it unavailable to your grass, explains Lemus.
- Timing mismatch: Lime can take months to change pH. If the soil is still acidic at fertilization time, plants won’t absorb nutrients effectively.
Best practices for applying lime and fertilizer
Whether you choose to apply lime and fertilizer together or separately, following some best practices will ensure you have the healthiest lawn and the most value from your efforts:
- Test your soil first: Always start with a soil test to determine your lawn’s pH and nutrient needs. The test report will tell you if your soil is acidic and needs lime, and how much to apply.
- Follow recommended rates: More is not better. Use the amount of lime suggested by your soil test and product label. Calibrate your spreader and measure your lawn area for even coverage.
- Choose the right time for application: Lawns should be fertilized during the grass type’s active growing season. For cool-season grasses, the best windows are fall and spring, while warm-season grasses respond best to fertilization in late spring and summer. Lime is different. According to turf specialists at Ohio State University Extension, lime can be applied any time the soil isn’t frozen and the grass isn’t stressed. Still, fall and early spring are the best choices.
- Water after application: Moisture activates fertilizer and dissolves lime so it can begin altering soil pH. A gentle rain can accomplish this, or you can use your sprinklers.
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Lime, fertilizer, and a helping hand
A healthy lawn needs both proper nutrition and the right soil conditions. Fertilizer feeds your grass, while lime balances the soil so those nutrients can be absorbed. Applying them at the right times will make your efforts more effective and save you money in the long run. If you’re unsure about your soil needs, LawnLove can connect you with a local lawn fertilizer pro. Their guidance can ensure your lawn gets exactly what it needs.
Sources
- PhD Alison O’Connor. Extension Professor of Horticulture. Colorado State University Extension. Personal Interview.
- “Does Your Lawn or Garden Need Lime?” By Charlotte Glen. Master Gardener. Horticultural Science. NC State University Extension.
- “Effects of Liming Materials on Soil pH.” By Rocky Lemus. Extension and Research Professor. Plant and Soil Sciences. Mississippi State University Extension.
- “Lime and the Home Lawn.” Ohio State University Extension.
- “Timing of Lime and Fertilizer Applications.” By Tracy Allen. University of Massachusetts Extension.
Main Image: Lawn fertilizer. Photo Credit: Tomasz Zajda / Adobe Stock
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