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A standard lab soil test reports pH, buffer pH, phosphorus, potassium, calcium, magnesium, organic matter percentage and cation exchange capacity — plus specific lime and fertilizer rates for the crop you name. It tells you what is limiting growth and how much of what to add, in pounds per 1,000 square feet. What it does not tell you is nitrogen, which moves too fast to measure usefully, or contaminants like lead, which is a separate add-on test. Cost through a state extension lab is roughly $10 to $25 as of 2026.
What is on a standard report?
| Measurement | What it tells you | Typical garden target |
|---|---|---|
| pH | Acidity or alkalinity; controls nutrient availability | 6.0–7.0 for most vegetables |
| Buffer pH | How much lime it takes to move the pH | Used to calculate the lime rate |
| Phosphorus (P) | Root and fruit development | Medium to optimum on the lab scale |
| Potassium (K) | Water regulation, disease resistance | Medium to optimum |
| Calcium and magnesium | Structure and cell function; Mg often low in sandy soils | Reported with a Ca:Mg relationship |
| Organic matter | Water holding, nutrient reservoir, biology | 4–6 percent is a good garden figure |
| Cation exchange capacity | How much nutrient the soil can hold | Under 10 sandy, 10–20 loam, 20+ clay |
| Micronutrients (often an add-on) | Iron, manganese, zinc, boron, copper | Rarely limiting in a home garden |
| Lime and fertilizer recommendation | Actual rates per 1,000 sq ft for your crop | The most useful line on the page |
Why is pH the most important number?
Because it controls whether the nutrients already in your soil are available to plants. Phosphorus locks up below about pH 5.5 and again above 7.5; iron and manganese become unavailable in alkaline soil, which is why blueberries and azaleas yellow in high-pH ground. A soil can test adequate in phosphorus and still starve the crop if the pH is wrong, which is why extension recommendations correct pH first and fertility second.
The buffer pH is the companion measurement and the one that makes a lab test worth paying for. Two soils at pH 5.5 can need very different amounts of lime depending on their clay and organic matter content, and buffer pH is how the lab calculates the actual rate. Home kits do not measure it, which is why they cannot tell you how much lime to apply. Lowering pH is the opposite problem and is covered in how to lower soil pH quickly.
What does a soil test not tell you?
- Nitrogen. Too mobile and too variable to measure meaningfully in a spring sample; labs infer it from your crop and organic matter instead.
- Lead and heavy metals. A separate add-on, typically $15 to $30, and worth ordering for urban yards, land near old painted structures, or soil close to a busy road.
- Soil texture. Sand, silt and clay percentages are usually a separate particle-size analysis, though CEC gives you a strong hint.
- Compaction and drainage. Physical problems that no chemical test detects — dig a hole and watch it drain.
- Biology. Standard tests do not count microbes, though organic matter percentage is a reasonable proxy for biological capacity.
- Herbicide residue. Persistent herbicides in compost or manure need a plant bioassay, not a lab panel.
How do you take a sample that gives a valid result?
- Sample each area separately. Vegetable beds, lawn and ornamental beds have different histories and different targets — do not blend them.
- Take 10 to 15 cores from across the area with a trowel or soil probe, to a depth of 6 to 8 inches for beds and 3 to 4 inches for established lawn.
- Mix them in a clean plastic bucket — not galvanized metal, which contaminates zinc readings — and take about two cups of the blend as your sample.
- Remove stones, roots and thatch, and let the sample air dry if it is wet.
- Fill in the crop and history section on the form. The recommendations are only as specific as the information you give the lab.
- Do not sample within 6 to 8 weeks of applying lime or fertilizer — timing is covered in when is the best time to test soil.
What do you do with the results?
Work down the report in order: correct pH first, then address any nutrient reported below optimum, then build organic matter. That last one is the slow lever and the most valuable — organic matter improves water holding, structure and nutrient retention at once, and compost is how you raise it. If your report comes back at 2 percent organic matter, an annual inch of compost worked into the top few inches is the standard prescription, and how to make compost covers producing it.
Reading the actual numbers on your report line by line is covered in how to read a soil test, lab pricing in how much a lab soil test costs, and if you want a quick pH check between lab tests our soil test kit picks cover the home kits worth owning. Clay soils have their own program, in how to improve clay soil.
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More from this hub: Composting & Soil · Compost versus topsoil · Reading a soil test · How we rank