Soil pH is crucial for a plant’s survival. If your soil doesn’t have a proper balance of acidity and alkalinity, your plants won’t be able to get the nutrients they need to flourish.
Strangely enough, the ideal level of soil acidity varies from plant to plant. That is, some plants do better in more acidic soils, while others thrive in a more alkaline environment.
If the soil is too acidic or alkaline, plants may still grow, they just may not grow as tall or produce as many leaves, fruit, and flowers.
In this article, we’ll be looking at the best soil pH for growing your herbs and how you can adjust the acidity level of your soil to suit the types of herbs you’d like to grow.
What Is pH and How Does It Affect Plant Growth?
Soil pH refers to the level of acidity in the soil. pH is measured on a scale from 0 to 14 with a value of 7 being neutral. Values less than 7 are on the acidic side of the equation and values greater than 7 are considered more alkaline.
Factors that can directly influence the acidity of soil include
- High levels of rainfall which carries away minerals such as calcium, magnesium, potassium, and sodium. The more rain the soil receives, the more acidic it usually is.
- Decomposing organic matter. Decomposition release carbon dioxide into the soil which creates more acid.
Plants get most of their essential nutrients from the soil. The pH value will determine how easily a plant can take in those nutrients.
Before a nutrient can be used by plants it must be dissolved in the soil solution. Most minerals and nutrients are more soluble or available in acid soils than in neutral or slightly alkaline soils.
SUNY College of envornmental science and forestry
What is the Best pH Range for Herbs?
Most of the herbs that you use in your kitchen will grow best in a Ph that is slightly below neutral – with a pH level between 6.0 and 7.5.
Each plant has a soil pH level that it best thrives in; certain herbs like their soil a bit more acidic. For example, Bay (Laurus nobilis) prefers pH levels around 6.2, while Fennel (Foeniculum dulce) prefers a soil pH that’s around 6.5.
Below is a table with the preferred pH level for most culinary herbs.
| Herb | Preferred pH |
|---|---|
| Basil | 5.5 – 6.5 |
| Bay | 6.2 – 6.8 |
| Chives | 6.0 – 7.0 |
| Dill | 5.8 to 6.5 |
| Garlic | 5.5 – 7.5 |
| Hops | 6.0 – 7.5 |
| Marjoram | 6.0 – 8.0 |
| Oregano | 5.8 to 6.2 |
| Parsley | 5.0 – 7.0 |
| Peppermint | 6.0 – 7.5 |
| Rosemary | 5.0 – 6.0 |
| Sage | 5.5 – 6.5 |
| Spearmint | 5.5 – 7.5 |
| Stevia | 6.7 – 7.2 |
| Thyme | 5.5 – 7.0 |
Source: The Gardener’s Network & Texas A&M Agri Life
How Do I Test My Soil’s pH?
Testing the pH level of your soil is super easy and quick as long as you have the right tools. A soil pH tester like the one shown below can be used to quickly test the pH level and moisture level of your soil.
With the help of such a tool, you’ll be able to accurately adjust your soil to the actual pH level you want. It also eliminates the guesswork that may lead to overly acidic or alkaline soil.
FAQs
Do any herbs thrive in acidic soil?
Most herbs like their soil in the slightly acidic side. But there are a few which can thrive with an even lower pH value. A few examples are:
- Basil
- Garlic
- Oregano
- Rosemary
- Thyme
How do I adjust the pH of my soil?
If the acidity level is too high, you can add limestone or wood ashes to raise the pH. And if it’s too alkaline, you can add sulfur to increase its acidity.
It takes about six months to adust your soil’s pH level, so give it time and be patient. Ideally, soil amendments are performed in the fall, so they have time to work before the planting season.
Make sure to use a soil pH tester to monitor the soil’s pH level as you adjust it. This will prevent over-adjusting the soil.
When making soil amendments, avoid overfertilizing. This can cause your herbs to grow too quickly and they won’t have time to develop the essential oils which give them their delightful aroma and flavor profiles.
Summary
If you want better results from your outdoor garden during your next growing season, be sure to test your soil and verify that its pH level is suitable for the herbs you want to grow.
Also, make sure that there’s proper soil drainage and that sufficient sunlight (at least six hours) reaches the site you intend to use for your herb garden.