Why Garden Soil pH is Important &
How to Use a Soil pH Tester

A good soil pH tester is an essential addition to every gardener’s tool box, since seeds planted in even the healthiest looking soil won’t grow well (or at all) in soil that is too acidic or too alkaline.

What is Soil pH?

Ideal Garden Soil pH

While most garden plants prefer a soil pH between 5.5 and 7.5, a few like it more acidic including azaleas, blueberries, potatoes and rhododendrons.

Soil pH is a sliding scale ranging from 1 to 14 that indicates how acidic or alkaline your soil is. One to 6.9 is acidic (with one being the highest level of acidity), 7 is neutral and 7.1 to 14 is alkaline (with 14 being the most alkaline).

In more simplistic terms, soil pH is the measure of lime in your soil. The more lime it has, the more alkaline it is. The less lime it has, as in the case of very sandy soil, the more acidic it will be.

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Why Garden Soil pH Matters

Plants need soil nutrients in order to grow and thrive. Those nutrients are only available to plants when they are dissolved in water which serves both to break down the nutrients into a small enough size for absorption and as medium for nutrient transfer (see Why Do Plants Need Water? for more information).

If your soil pH is either too acidic or too alkaline, most soil nutrients will not dissolve and therefore not be absorbed by the plant.

A healthy plant growing in nutrient-rich soil with an optimal plant-specific pH level will not only grow faster and fuller and provide a more nutritious harvest, it will also be much more able to fend off pests and disease.

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Instructions for Testing Soil pH with a Soil pH Tester

Each plant has a preferred soil pH range (as indicated on the plant-specific pages throughout GrowingAnything.com), and your goal should be to keep each plant’s soil within 0.5 of their preferred range. If the number falls more than 0.5 outside the desired range, soil pH adjustment is in order.

Soil pH test kits also test for nitrogen (N), phosphorous (P) and potassium (K) in the soil and are relatively straightforward to use.

soil ph tester

We like the AccuGrow Soil Test Kit, which provides enough materials to allow you to complete 10 separate tests. To test your soil’s pH with this model, simply dip the included test strips into your soil sample and the results will for pH, nitrogen, phosphorous and potassium will display within minutes.

When obtaining the soil for your test…

  • Test before amending your soil. To get a true understanding of soil’s makeup, test before you add any organic garden fertilizers.
  • Use warm soil that is not overly wet or dry.
  • Take a sample from several parts of your garden, especially when testing for multiple plants with different pH requirements. For each larger bed that requires consistent soil pH (you’re plants in that bed tolerate a similar pH range), take samples from multiple locations and thoroughly break up and mix them together for your test.

Be sure to document your test results including your pH, N, P and K levels, the date and where in your garden the soil samples came from.

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