Should you test your soil before lawn or garden work, and how?

Updated November 10, 2026 · KeystoneProGuide editorial team

Should you test your soil?

Before you fertilize, lime or start a new lawn, yes. Penn State Extension says the only way to determine how much phosphate and potash turf requires is a soil test, and that lime should be applied only on a soil test recommendation. The Department of Agriculture, which enforces the state's fertilizer law, calls the test simple and inexpensive and tells homeowners to start there: "No more guess work."

The test is also the cheapest piece of most landscaping projects. In Bucks County, Penn State's extension office sells the kit for $10.00.

What does a soil test tell you?

The standard Penn State test is a fertility test. The Montgomery County Master Gardeners say it measures soil pH and the levels of phosphorus, potassium, calcium and magnesium, recommends amounts of lime and fertilizer, and makes a nitrogen recommendation. Penn State notes that a lawn's actual nitrogen need cannot be measured by a soil test, so that part of the report is a recommendation, not a reading.

pH matters most for many lawns. Penn State says most turfgrasses prefer a soil pH of 6.0 to 7.0, and that keeping the pH in that range also favors the soil microbes that break down thatch.

Why does Pennsylvania's fertilizer law make the test more useful?

Because of phosphate. The Department of Agriculture explains that the state restricts phosphate in lawn fertilizer: phosphorus moves with runoff, and high levels in water promote excessive algae. The law allows no phosphate unless you are establishing, re-establishing or repairing turf or using an enhanced-efficiency product, and the department says that where a soil test shows phosphate is needed, a site-specific amount can be applied. A soil test is therefore the document that tells you, and a lawn care company, whether phosphate belongs in the program at all.

The Montgomery County Master Gardeners make the practical point: soil tests often save money by revealing that adequate nutrients are already present.

How do you take a sample?

The Montgomery County Master Gardeners give the method for a lawn:

1. Define the area. A lawn, a flower bed and a vegetable garden are separate samples.
2. Sample widely. Criss-cross the area and take soil from 12 to 15 spots.
3. Go 3 to 4 inches deep for turf. For other plants they suggest 6 to 8 inches.
4. Clean it. Throw out stones, sod and thatch, and mix the samples in a clean container.
5. Dry it. Air-dry the soil before mailing. Do not heat it.
6. Mail it with the questionnaire in the kit.

Results come back in about 7 to 10 days. For a new lawn, Penn State's establishment guide says to sample three to four weeks before preparing the soil, so the report arrives before the topsoil and amendments are ordered.

Where can you get a kit?

From any Penn State Extension county office, or by downloading the form and mailing about a cup of soil directly to Penn State's laboratory. In the five counties this directory covers:

What does the standard test not cover?

Contaminants. The Montgomery County Master Gardeners say it does not check for pesticide residue, gas, oil or other pollutants. Lead is the one most homeowners should think about. Penn State Extension says soil near older homes, especially close to painted foundations, can carry very high lead levels, that homes built before 1978 are more likely to have used lead paint, and that young children are most at risk. It recommends testing soil for lead around older homes, near roads, in play areas and in vegetable gardens, and asking the laboratory for total lead. Penn State's laboratory is one of several in Pennsylvania that offer it.

Is a "soil test" from a landscaper the same thing?

Not necessarily. Angi, a cost survey, lists "soil testing" at $700 to $2,050 as a land preparation cost, without saying what the test is. That is not the price of a lawn and garden fertility test, which the Bucks County extension office sells for $10.00. If a quote includes soil testing, ask which test, from which laboratory, and whether you will get the report.

The Department of Agriculture suggests asking any lawn care provider whether it conducts a soil test to decide what your lawn needs. A company that does should be able to show you the report and explain how its program follows it. For the rules that govern what it then applies, see the fertilizer law guide. For checking the company, see how to choose a landscaper, and local businesses are on the landscapers directory page.

Sources

1. Lawn Management through the Seasons, Penn State Extension
2. Lawn Establishment, Penn State Extension
3. Homeowners and Applicators, Pennsylvania Department of Agriculture
4. Fertilizer FAQs, Pennsylvania Department of Agriculture
5. Soil Testing (Montgomery County Master Gardeners), Penn State Extension
6. Soil Testing Information (Bucks County Master Gardeners), Penn State Extension
7. Soil and Water Testing Information (Philadelphia County Master Gardeners), Penn State Extension
8. Garden Hotline (Chester County Master Gardeners), Penn State Extension
9. Garden Hotline (Delaware County Master Gardeners), Penn State Extension
10. Lead in Residential Soils: Sources, Testing, and Reducing Exposure, Penn State Extension
11. How Much Does Landscaping Cost? [2026 Data], Angi