Soil pH is measured on a scale from 0 to 14. A pH of 7.0 is neutral, values below 7.0 are acidic, and values above 7.0 are alkaline. Most lawn grasses prefer slightly acidic soil because nutrients are most available in that range.
The chart below provides a complete overview of ideal lawn pH levels for all common grass types, symptoms of incorrect pH, and recommended soil amendments.
Lawn pH Level Chart
| Grass Type | Grass Category | Ideal Soil pH Range | Too Acidic Symptoms | Too Alkaline Symptoms | Recommended pH Adjustment |
|---|---|---|---|---|---|
| Kentucky Bluegrass | Cool-Season | 6.0 – 7.0 | Yellowing, thin turf, poor root growth | Iron deficiency, slow growth | Lime to raise pH, sulfur to lower |
| Perennial Ryegrass | Cool-Season | 5.5 – 7.5 | Weak growth, nutrient lockout | Pale color, reduced vigor | Lime or elemental sulfur |
| Fine Fescue | Cool-Season | 5.0 – 6.5 | Poor density, moss growth | Patchy growth | Lime for acidic soil |
| Tall Fescue | Cool-Season | 5.5 – 7.0 | Brown patches, weak roots | Yellowing leaves | Lime or sulfur as needed |
| Creeping Bentgrass | Cool-Season | 5.5 – 6.5 | Reduced nutrient uptake | Chlorosis | Sulfur for high pH |
| Annual Ryegrass | Cool-Season | 5.5 – 7.0 | Slow establishment | Light green color | Lime or sulfur |
| Bermuda Grass | Warm-Season | 5.5 – 7.0 | Stunted growth, thinning | Iron chlorosis | Lime for acidic soil |
| Zoysia Grass | Warm-Season | 6.0 – 6.5 | Yellow patches, slow spread | Poor nutrient absorption | Sulfur for alkaline soil |
| St. Augustine Grass | Warm-Season | 5.5 – 7.5 | Root damage, poor density | Pale blades | Lime or sulfur |
| Centipede Grass | Warm-Season | 5.0 – 6.0 | Reduced growth if too acidic | Severe iron deficiency | Rarely needs lime |
| Bahia Grass | Warm-Season | 5.5 – 6.5 | Thin turf | Yellowing leaves | Lime sparingly |
| Carpet Grass | Warm-Season | 4.5 – 6.0 | Poor growth in extreme acidity | Nutrient lockout | Lime if pH drops too low |
| Buffalo Grass | Warm-Season | 6.5 – 7.5 | Poor drought tolerance | Nutrient imbalance | Sulfur to reduce pH |
| Kikuyu Grass | Warm-Season | 5.5 – 7.0 | Weak runners | Pale green color | Lime or sulfur |
| Bentgrass (Putting Greens) | Specialty | 5.0 – 6.0 | Moss invasion | Yellowing | Sulfur for control |
| Blue Grama | Native | 6.0 – 7.5 | Reduced growth | Iron deficiency | Sulfur if alkaline |
| Red Fescue | Cool-Season | 5.0 – 6.5 | Weak color | Thin growth | Lime cautiously |
| Orchard Grass | Utility | 5.8 – 7.0 | Poor nutrient uptake | Slow establishment | Lime or sulfur |
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Why Lawn pH Matters
Soil pH determines how easily grass can access nutrients in the soil. When pH is outside the recommended range, nutrients become chemically bound and unavailable to roots. This condition is often mistaken for a fertilizer deficiency when the real issue is improper pH.
At low pH levels, aluminum and manganese can become toxic to grass roots. At high pH levels, iron and phosphorus become less available, leading to yellowing and weak growth.
Signs Your Lawn pH Is Too Low or Too High
A lawn that struggles despite watering and fertilizing may have an underlying pH problem. Common indicators include persistent yellowing, slow growth, moss invasion, weak root systems, and patchy turf. Soil testing is the only reliable way to confirm pH levels.
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How to Test Lawn Soil pH
You can test lawn pH using home soil test kits, digital soil meters, or professional laboratory testing. For accuracy, collect soil samples from multiple areas of the lawn and test at least once every two to three years.
How to Adjust Lawn Soil pH
To raise soil pH (make soil less acidic), agricultural lime is commonly used. Pelletized lime is easier to apply and works gradually. To lower soil pH (make soil more acidic), elemental sulfur or soil acidifiers are effective. Adjustments should be made slowly, as drastic changes can damage grass.
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Best pH Range for Most Lawns
For mixed lawns or general turf, a soil pH between 6.0 and 6.8 is considered ideal. This range allows maximum nutrient availability and supports healthy root development for most grass species.
FAQs
What is the best pH level for lawns?
The best pH level for most lawns falls between 6.0 and 6.8, which is slightly acidic. This range allows grass to absorb essential nutrients like nitrogen, phosphorus, potassium, iron, and magnesium efficiently.
While some grasses can tolerate a wider range, staying within this window promotes stronger root growth, greener color, and better resistance to weeds, pests, and disease.
What does a low pH lawn look like?
A lawn with low pH (acidic soil) often appears thin, weak, and patchy, with grass that turns yellow or pale green even after fertilization. Moss and weeds such as sorrel and plantain may begin to dominate. Root growth becomes shallow, and grass may struggle to recover from stress caused by drought, foot traffic, or mowing.
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What happens if lawn pH is too high?
When the lawn pH is too high (alkaline soil), grass may show iron deficiency, resulting in yellow blades with green veins. Growth slows, fertilizer becomes less effective, and the lawn may look dull or washed out. Certain nutrients become chemically unavailable, leading to poor turf density and increased susceptibility to disease.
Does lime raise or lower pH?
Lime raises soil pH, making acidic soil less acidic. It is commonly applied to lawns with low pH to improve nutrient availability and root development. Agricultural or pelletized lime works gradually, so results may take several months. Lime should only be applied after soil testing confirms acidity.
How to tell if a lawn is too acidic?
The most reliable way to tell if a lawn is too acidic is through a soil pH test using a home test kit or laboratory analysis. Visual signs include yellowing grass, poor growth despite fertilizing, moss invasion, and weak roots. If these symptoms persist, soil testing will confirm whether pH correction is needed.
Final Thoughts
A lawn pH level chart is an essential reference for maintaining thick, green, and healthy turf. Understanding your grass type and matching it with the correct soil pH range ensures better fertilizer efficiency, stronger roots, and improved resistance to weeds and disease.
By testing soil regularly and making gradual adjustments, homeowners can significantly improve lawn performance and long-term health.
