If the plants in your garden are struggling, poor soil acidity could be the reason. All gardeners should be familiar with the pH levels in soil and how to make soil more or less acidic. It also helps to understand the specific acidity preferences of the plant varieties in your garden. Here's a quick primer.
Acidic Soil and Garden Health
The alkalinity or acidity of soil is governed by numerous factors. It has a lot to do with mineral content, and the acidity can also be affected by local geology.
Acidity and alkalinity in soil is measured on something called the pH scale. This scale contains numbers from 0–14, with 7 being the median. Soil with a pH level below 7 is considered acidic. When the number exceeds 7, the soil is alkaline.
The pH level of soil affects a plant's ability to absorb the nutrients it needs to thrive. Nitrogen, potassium and calcium are examples of nutrients that are passed on from soil to your plants. These nutrients are maintained and developed in healthy soil, and that means maintaining a proper pH level.
What Plants Like Acidic Soil?
You may be discouraged by the thought of having to monitor and maintain the proper acidity in your garden soil. What seems like a lot of effort is actually easy with the modern tools that are available. You can collect your own samples and test the pH level in minutes.
There is even more good news. Most plants and turf grasses prefer soil that is a little acidic. A pH level of between 6 and 6.5 will be beneficial for most garden varieties. However, there are a few plants that need a more acidic soil environment.
Evergreen shrubs like azalea and gardenia need more acidic soil to look and feel their best. Gardens with holly and rhododendron should also have a more acidic environment.
Zinnia, camellia and begonia plants are examples of flowers that require acidic soil. Vegetables are also affected by pH levels, with peppers, potatoes and radishes thriving at low pH readings.
A lower pH level in soil will also be required for the optimum health of your blueberries, cranberries and currants.
The important thing to remember is that you need to get a feel for the ideal soil conditions by monitoring growth and making some notes. Do regular testing, and don't be afraid to adjust the acidity of your garden soil in small increments to see which plants are affected in a positive way.
How To Increase Soil Acidity
There are multiple methods for increasing acidity in soil. These are generally referred to as soil amendments. The type of soil amendment that you choose will depend on various factors.
Before you apply soil amendments in an effort to increase soil acidity, you will want to have a good test of your soil. This is one of those times when you may want to pay for professional assistance. Doing your own test for monitoring can be useful, but a proper soil test prior to each new gardening season can help you take the right measures.
Acid fertilizer comes in very handy when you have a garden that includes plant varieties with different soil needs. This fertilizer can be applied to individual plants when you don't want to adjust the overall pH level of the soil.
You can use any of the following to lower the pH level in your garden soil:
- Iron Sulfate
- Sphagnum Peat Moss
- Ammonium Sulfate
Some amendments like iron sulfate work faster than other products, but they also require a heavier application. Others, like sphagnum peat moss, come with the added benefit of adding organic material to your soil. These amendments can increase the acidity of soil for up to two years.
Learning how to make soil acidic is a worthy investment of your time if you are an active gardener. There is a noticeable difference in the health of plants that are growing in a proper soil environment. Don't worry about getting things perfect in the beginning. Soil management is a learning process. You will learn more with every passing season.
For more information on soil preparation, read the following articles: