Last Updated on September 10, 2021 by Paul Guzman
Changing pH in Soil – Acid or Alkaline Conditions. So what exactly is pH? In layman’s terms, it means a scale used to specify the acidity or alkaline conditions of the soil. Ideally, you want a neutral reading on a pH meter. But some plants like acidic soil and others like alkaline soil.
In and around the Southwest USA region the soil is often alkaline. The drought conditions and lower rainfall throughout the year is the main reason for alkaline soil. In regions where there is lots of rainfall, the soil will be acidic.
However, it is always best to test your soil so that you can determine what to plant during the growing season. Using a good pH test meter from your local nursery store will do the job.
Most plants like a Neutral Reading
The image above has the needle at 7 or neutral. These are ideal soil conditions no matter where you live. Changing the reading can be done by adding soil fertilizers, compost, manure, or other nutrients depending on what plants you want to grow.
How to make your soil more acidic
Tomatoes and chile plants like acidic soil while Yucca’s, Yarrow’s, and many others like plants like alkaline soil. For a tomato and or a chile garden, it’s best to have soil register around 6.5 or slightly acidic.
The most common way is to incorporate some limestone into your soil. Adding ammonium sulfate will also make your soil more acidic, but too much and it can burn the root system of plants. A safer way is to use Sphagnum peat moss in your soil. You can also purchase acidified fertilizers at most garden nursery stores. Often times all you need is to amend your soil with well-composted soil.
Plants that like Acidic Soil
Don’t overthink it… you can incorporate then test with a store-bought pH soil tester. Ideally, you want a 5.5 or 6. Remember the lower the number the MORE acidic. The HIGHER the number the more alkaline. It took me a long time to understand this simple logic!
How to make your soil Alkaline
Ok, so now we want to make your soil more alkaline right? Add some dolomite to increase alkaline conditions in your soil. Ornamental Plants like Barberry, Photinia, and Lilacs like alkaline soil. Edible plants like Kale, Peas, Asparagus, and Cauliflower will also do well in alkaline soil. Ideally, you want to have the test measure at about 8.5 or 8.
The most important thing to know is that purchasing good store-bought compost and incorporate this with your native soil will lower or raise acidic or alkaline levels in the soil. If your test is too acidic or alkaline your plants will have a hard time taking in the proper nutrients for good overall growth.
Plant nutrition is needed for all plants, they need Nitrogen, Phosphorus, and Potassium. There are other nutrients and minerals but these are the most important.
You can also ask your local Soil Testing Labs at Cooperative Extension Offices to test your soil. Currently, many of these state offices are closed due to COVID-19.
Changing pH in Soil – Acid or Alkaline Conditions