garden soil ph and ec testing - Ask Extension
I recently purchased Apera Instruments PH20 pH and Apera Instruments EC20 Conductivity Testers. These are reviewed as highly accurate testers with buf...
Knowledgebase
garden soil ph and ec testing #929257
Asked April 22, 2026, 3:32 PM EDT
I recently purchased Apera Instruments PH20 pH and Apera Instruments EC20 Conductivity Testers. These are reviewed as highly accurate testers with buffered calibrations solutions so I'd like to get the most accurate measurements I can. However, they do not test in soil. They only test in liquids. My question is what is the best ratio of neutral water to soil for accurate PH and EC testing, and are measurements of soil by weight or volume? I suppose soil by weight will vary based on moisture already present in the soil.
Baltimore County Maryland
Expert Response
Are you a home gardener or using these tools in a commercial nursery operation? You may want to enquire with Extension horticulture specialist Andrew Ristvey, who has experience measuring pH and EC in soils and potting media. Andrew works with horticulture businesses, but can still answer these questions (which are beyond HGIC's area of expertise) if you're a home gardener. He's not on the Ask Extension platform, but can be reached via the contact information in the linked page.
Miri
Miri
John, Andrew got back to me regarding your question, and he has this advice: "Labs take soil samples and mix with distilled water to make a runny paste (SME) or they do a 1-to-1 volume-to-volume for pH. That is then vacuum-filtered with a 45 um filter to make a clear sample liquid. A pH reading is less dependent on the volume of water than EC is. Plus, a soil is typically not tested for EC because the mineral content can mess up the readings." (It's soilless mixes that are tested.)
We hope that helps, as this level of detail is outside of our expertise at HGIC. If you're a commercial grower (nursery, cut flowers, etc.) then Andrew will be able to help more one-on-one with any soil, nutrient, or water quality issues.
Miri
We hope that helps, as this level of detail is outside of our expertise at HGIC. If you're a commercial grower (nursery, cut flowers, etc.) then Andrew will be able to help more one-on-one with any soil, nutrient, or water quality issues.
Miri
