Knowing how to test your soil’s pH will help you understand which plants will grow better in your soil. In Bozeman, the soil tends to be slightly alkaline. Soil pH affects nutrient availability, plant health, and even soil microbes. Different plants had preferences for different acidity levels in soil. You can also add amendments to your soil to change its pH, and soil testing will help you achieve the right balance.

Why Soil pH Matters

Soil pH measures the acidity or alkalinity of your soil on a scale of 0 to 14, with 7 being neutral. Acidic soils (below 7) are common in areas with high rainfall, while alkaline soils (above 7) are often found in drier regions like Bozeman.

Different plants thrive in different pH ranges. For example:

• Acid-loving plants (pH 4.5–6.5): Blueberries, rhododendrons, azaleas
• Neutral to slightly acidic plants (pH 6.0–7.0): Tomatoes, carrots, beans
• Alkaline-tolerant plants (pH 7.0–8.0): Lavender, lilacs, asparagus

If your soil’s pH is too high or too low, your plants may struggle to absorb nutrients, leading to poor growth and yellowing leaves.

How to Test Your Soil’s pH

There are several ways to test your soil’s pH, ranging from simple DIY methods to professional lab tests.

1. Use a Home Soil Test Kit

One of the easiest ways to determine your soil’s pH is with a home test kit, available at garden centers or online. These kits typically include test strips or capsules that change color based on pH levels. Here’s how to use one:

1. Collect a small soil sample from different areas of your garden (about 2–4 inches deep).
2. Mix the samples in a clean container and remove debris.
3. Follow the kit instructions, which usually include adding water to the sample and inserting a test strip or capsule.
4. Compare the color change to the chart provided with the kit.

The benefit of using a kit is it is low-cost and easy to use. When I first started my garden, I bought an inexpensive kit at Lowes. However, I realized partway through the season that I needed to test different areas of my garden multiple times. Therefore, purchasing a pH meter may be a better option.

2. Use a pH Meter

A digital pH meter provides a more accurate reading than test kits. It is also reusable and should last for several years. To use one:

1. Insert the probe into moist soil (or mix soil with distilled water for better accuracy).
2. Wait for the reading to stabilize.
3. Clean the probe after each use to maintain accuracy.

3. Send a Sample to a Lab

For the most precise results on how to test your soil’s pH, send a sample to a local extension service or agricultural lab. Many university extension offices offer soil testing, including recommendations for amendments based on your results. However this method will take time and patience, and you will not be able to do this many times in a growing season. Unless you’re friends with someone in MSU’s lab, this is probably not a practical option!

Adjusting Your Soil’s pH

If your soil’s pH isn’t ideal for the plants you want to grow, you can adjust it:

• To Lower pH (Make Soil More Acidic)
  • Add elemental sulfur or aluminum sulfate.
  • Incorporate organic matter like peat moss, coffee grounds, or pine needles.
  • Use acidifying fertilizers such as ammonium sulfate.
• To Raise pH (Make Soil More Alkaline)
  • Add agricultural lime (calcium carbonate) to neutralize acidity.
  • Use wood ash sparingly as a natural alkaline amendment.
  • Grow alkaline-tolerant plants instead of altering the soil significantly.

Testing your soil’s pH is an essential step in gardening success. Knowing your soil’s characteristics allows you to choose the right plants and make necessary amendments for optimal growth. Whether you use a simple home test or a professional lab analysis, understanding your soil’s pH will help ensure a thriving, beautiful garden wherever you plant!