Soil

Updated May 23, 2025

Soil pH testing

Best Practice

  • Always prepare a soil-water slurry (soil mixed with distilled water) and dip the strip into the clear liquid portion for a reliable reading.

Here’s a quick protocol to test soil pH directly with pH strips, minimizing errors while skipping the slurry step:

Quick Direct Soil pH Test Protocol

Step

Action

1

Collect soil sample from 4–6 inches depth, mix multiple spots for representativeness

2

Remove large debris, roots, stones, and break up clumps for fine soil consistency

3

If soil is dry, moisten slightly with distilled water — just enough to make it damp (not muddy)

4

Take a clean, dry pH strip and gently press it against the moist soil surface or slightly insert into soil for 5–10 seconds

5

Remove strip and compare immediately to color chart provided with strips

6

Repeat 2–3 times at different spots for average reading

Notes

  • Use distilled water to avoid altering pH.
  • Avoid overly wet soil to prevent dilution of the strip reagent.

 This method gives an approximate pH; for more precision, the slurry method or digital probe is preferred.


Slurry Method

Step

Action

1. Collect Soil

Take a sample 4–6 inches deep from several locations in your bed. Mix well.

2. Air-Dry (Optional)

Let soil dry if excessively wet; do not oven-dry. Not necessary unless testing multiple times.

3. Make a Slurry

Mix 1 part soil with 2 parts distilled water in a clean container. (e.g., 1/2 cup soil + 1 cup water)

4. Stir and Settle

Stir thoroughly and let it sit for 15–30 minutes. Stir again before testing.

5. Dip the Strip

Insert a pH strip into the water (not the soil itself) for 1–3 seconds.

6. Read Immediately

Match color to the pH scale provided with your strips within 10–15 seconds.

7. Record

Average the readings if you test multiple spots.

Accuracy Tips

Tip

Reason

Use distilled water

Tap water may contain minerals that skew pH

Test multiple areas

Soil pH can vary widely across a garden

Avoid testing after fertilizer application

Wait at least 1–2 weeks to avoid misleading results

 


Can I use pH strips directly on wet soil?

 

No, it’s not recommended to use pH strips directly on wet soil because:

  • Soil particles can stick to the strip, causing inaccurate color changes.
  • The moisture in soil is uneven, leading to inconsistent pH readings.
  • Soil contains solids and organic matter that interfere with proper strip contact.

 

Interpreting pH Readings

pH Range Soil Reaction Plant Suitability
4.5–5.5 Strongly acidic Blueberries, azaleas, rhododendrons
5.6–6.5 Moderately acidic Most vegetables, shrubs, fruit trees
6.6–7.3 Neutral General-purpose gardening, turfgrass
7.4–8.5 Alkaline Lavender, lilac, some grasses

Composition

Kiss the Ground (book and movie)

Related Links

US Government (National Weather Service) **

** new browser tab will open