Question 1

What does my soil pH mean for my lawn?

Accepted Answer

Soil pH controls nutrient availability. Most lawn grasses prefer slightly acidic to neutral soil (6.0–7.0). At extreme pH levels, nutrients get locked in the soil and your grass can’t absorb them — no matter how much fertilizer you apply. Centipede grass is the exception, preferring acidic soil (pH 5.0–6.0).

Question 2

How often should I test my soil?

Accepted Answer

Test every 2–3 years for general maintenance. If you’ve applied major amendments like lime or sulfur, retest 6–12 months after application to check your progress. The best time to test is fall or early spring before you start applying products.

Question 3

What is a good NPK level for lawns?

Accepted Answer

It depends on your test provider’s scale. On a MySoil test, nitrogen 7–18 ppm, phosphorus 5–11 ppm, and potassium 38–72 ppm are optimal. Extension lab tests use a different extraction method with higher numbers: phosphorus 25–50 ppm and potassium 150–250 ppm. Always compare your numbers to your specific lab’s ranges.

Question 4

How do I lower my soil pH?

Accepted Answer

Apply elemental sulfur at 5–10 lbs per 1,000 sqft. Sulfur takes 3–6 months to lower pH, so apply in fall or spring. Do not exceed 10 lbs per application. Retest before reapplying. Aluminum sulfate works faster but can be harsher on the soil.

Question 5

How do I raise my soil pH?

Accepted Answer

Apply pelletized lime at 25–50 lbs per 1,000 sqft depending on how far below your target you are. Lime takes 2–3 months to work. Apply in fall for the best spring results. Important exception: never lime centipede grass unless pH drops below 5.0.

Question 6

What do ppm values mean on a soil test?

Accepted Answer

PPM stands for parts per million. It measures the concentration of each nutrient in your soil. Different labs use different extraction methods (MySoil vs Mehlich-3 vs saturated paste), so the same soil can produce different ppm numbers depending on the test. Always interpret your results using your specific lab’s recommended ranges.

Question 7

Why are MySoil ranges different from extension lab ranges?

Accepted Answer

MySoil and university extension labs use different chemical extraction methods to pull nutrients from your soil sample. MySoil extracts fewer total nutrients, so their optimal ranges are lower numbers. A phosphorus reading of 8 ppm on MySoil might be “Optimal,” while the same soil tested at an extension lab might read 35 ppm — also optimal for that scale. Neither is wrong; they’re just different measurement systems.

Question 8

Do I need to lime my lawn?

Accepted Answer

Only if your soil test shows pH below your grass type’s ideal range. Never apply lime based on a guess — over-liming raises pH too high and locks out iron, causing yellow grass. Centipede grass owners should almost never lime (centipede prefers acidic soil pH 5.0–6.0).

Question 9

How do I fix low potassium in my lawn?

Accepted Answer

Apply Muriate of Potash (0-0-50) at 2 lbs per 1,000 sqft. Available on Amazon or at SiteOne Landscape Supply. Potassium builds heat, cold, and drought tolerance. Apply in late spring or early fall. Low potassium is one of the most common soil deficiencies in lawns.

Question 10

What is the best soil test kit for lawns?

Accepted Answer

MySoil (~$30 on Amazon) is the most popular consumer option — easy to use and tests all 13 nutrients. For the most accurate results, use your state’s university extension lab ($15–25) — find yours at extension.org. SoilKit is another solid consumer option. Avoid cheap pH-only probe testers; they’re not accurate enough for amendment decisions.

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