The pH value of your soil has a significant effect on the nutrients that are available for your plants. If you recently discovered that your garden soil is on the acidic side, you might think your plant options are limited.
On the contrary, there are a wide range of plants that thrive in acidic soil. Woody shrubs like roses, vegetables such as asparagus, and most fruit trees grow best in soil with pH levels below 7.
While the above plants are known as acid-lovers, that doesn’t mean you need to rush to acidify your soil further. This article will discuss how to tell whether you should alter your garden’s pH level, how to do it, and give examples of plants that prefer acidic soil.
Which Plants Like Acidic Soil?
Let’s start with a quick refresher on acidity levels, since if you’re anything like me, you may have assumed that you’d never have to worry about pH levels after grade school science. If you’re not, you already know that soil pH refers to the measure of acidity and alkalinity in a section of land.
Acidity levels are measured using a scale of 0.0-14.0:
- 0.0 is the most acidic on the scale,
- 7.0 is considered neutral, and
- 14.0 is the most alkaline.
Anything that registers below a pH of 7.0 is considered acidic. Although this can be broken down further into degrees of acidity (such as slightly or moderately acidic), this article will use a broad overview.
Here are some popular ornamentals and shrubs that grow well in acidic soil:
| N a m e | Z o n e | p H | T y p e |
|---|---|---|---|
| Bleeding Heart | 2-9 | 6.0-6.5 | Herbaceous plant with heart-shaped flowers that bloom from spring until summer. Light shade to full sun. |
| Ostrich Fern | 3-7 | 5.5-6.5 | Deciduous plant with green fronds that reach heights of up to 4 feet tall. Part shade to full shade – keep out of direct sunlight. |
| Bee Balm | 3-9 | 6.0-7.5 | Flowering plant with red, pink, purple, or white blooms in summer. Full sun. |
| Creeping Phlox | 3-9 | 6.0-8.0 | Herbaceous flowering plant that blooms in late spring to early summer. Full sun to partial shade. |
| Rhodo- dendron | 4-8 | 4.5-6.0 | Large genus of trees, shrubs, and vines that bloom from spring – fall. Full sun in zones 3-6. Morning sun in tropical regions (Zones 7-11). |
| Caladium/ Elephant Ear | 8-12 | 5.5-6.5 | Tropical plant with seasonal dormancy in fall/winter. Indirect light indoors. Full to partial shade outdoors. |
| Daylily | 4-9 | 6.0-8.0 | Herbaceous plant which grows in clumps that bloom from spring to late summer. Full sun to part shade. |
| Blueberry Bush | 3-6 | 4.0-6.0 | Upright bush with woody canes that produce fruit in June. Full sun to partial shade. |
| Pachy- sandra | 3-9 | 5.5-6.5 | Evergreen ground cover that grows in partial to full shade. |
| Gladiolus | 8-10 | 5.0-7.0 | Flowering plant that grows from bulbs and blooms from June until frost. Full sun. |
flowers. It prefers a soil pH of 6.0 to 6.5, and is hardy in Zones 2 through 9. This plants prefers light shade to full sun.
Note: If you’re not sure what your growing zone is, check out the US Department of Agriculture’s Plant Hardiness Zone Map.
Please note that while we’ve provided a general range for each plant’s growing zone, always read the information tags on any plant you purchase to ensure the particular variety is suitable for your conditions.
Vegetables That Like Acidic Soil
| N a m e | Z o n e | p H | T y p e |
|---|---|---|---|
| Carrot | 3-10 | 5.5-7.0 | 6-10 hours of direct sun each day |
| Potato | 3-10 | 4.8-6.5 | At least 6 hours of direct sunlight per day |
| Garlic | 1-5 | 5.5-8.0 | 6-8 hours of direct sunlight per day |
| Asparagus | 3-8 | 6.0-8.0 | Minimum of 8 hours of sunlight each day |
| Cauliflower | 2-11 | 5.5-7.5 | At least 6 hours of full sun per day |
| Bell Pepper | 9-11 | 5.5-7.0 | At least 6 hours of full sun per day |
| Broccoli | 2-11 | 6.0-7.0 | Minimum of 6 hours of full sun each day |
| Celery | 2-10 | 5.8-7.0 | At least 6 hours of full or partial sun every day |
| Cucumber | 4-10 | 5.5-7.0 | 6-8 hours of direct sunlight per day |
| Squash | 3-10 | 5.5-7.0 | Minimum of 6 hours of direct sun per day |
Trees That Like Acidic Soil
| N a m e | Z o n e | p H | T y p e |
|---|---|---|---|
| Sugar Maple | 4-9 | 6.0-7.5 | Minimum of 4 hours of direct sun each day |
| Dogwood | 3-8 | 5.0-7.0 | Prefers partial shade but can tolerate full sun |
| White Pine | 3-7 | 4.5-6.0 | At least 4 hours of direct sun each day |
| Apple | 3-8 | 5.0-6.5 | At least 8 hours of full sun per day |
| Spruce | 3-8 | 5.0-6.0 | Minimum of 6 hours of unfiltered sunlight each day |
| Birch | 2-6 | 5.0-6.5 | 6 hours of full sun per day |
| Hemlock | 3-8 | 5.0-6.0 | 6-8 hours of direct sunlight each day |
| Chestnut | 4-9 | 5.0-6.5 | At least 8 hours of direct sunlight per day |
| Willow | 4-10 | 6.0-8.0 | Minimum of 4 hours of unfiltered sunlight per day |
| Juniper | 5-9 | 5.0 – 6.0 | 6-7 hours of direct sun each day |
Do Hydrangeas Like Acidic Soil?
According to the Texas A&M Agrilife Extension, many hydrangeas cannot survive in soil that is not acidic. Generally, soil with a pH of less than 5.5 is ideal for most types of hydrangeas.
Depending on the variety you grow, you can even change the color of your hydrangea’s flowers by changing the acidity levels. However, this is easier to do when you grow them in containers since you can better control the pH levels.
Do Roses Like Acidic Soil?
Roses generally receive optimal nutrition when the soil’s pH is around 6.0. This works out for much of the eastern United States, where the soil is commonly slightly acidic.
If your garden is more on the alkaline side and your roses are thriving, there is no need to change it. Most garden centers carry fertilizer specially formulated for roses and will provide the necessary amount of acidity.
Do Tomatoes Like Acidic Soil?
Tomatoes are well-known acid-loving plants that prefer to grow at pH levels between 5.5-7.0. Some research indicates that tomato plants grown in alkaline soil do not yield harvests as successful as those produced in higher acidity.
Fertilizers formulated for tomato plants can often provide the nutrients they might not receive from the soil otherwise, such as nitrogen, phosphorus, and potassium.
How To Acidify Soil
Before you make your soil more acidic, you should figure out whether it’s necessary. If you are currently growing plants that technically need more acidic soil than you have, but your plants are performing well, there’s no need to change anything.
But if your acid-loving plants seem to be struggling, here’s what you can try:
Step 1: Assess The Symptoms
Your plants are the best indicator of whether something isn’t quite right in the garden. Small, pale green or yellow leaves with comparatively green veins are common signs that the soil pH is too high.
You may also notice brown edges on any new growth. If acidity levels are indeed the culprit, your plant could eventually die.
Step 2: Test Your Soil
Since symptoms of nutrient deficiency can overlap with other plant problems, it’s a good idea to test your soil’s pH before altering it. The easiest way is to pick up a soil testing kit at your local garden center. These kits can determine how acidic your soil is with considerable accuracy.
Follow the instructions on the test kit. If the pH level is below 7, your soil is acidic, and you should consider other diagnoses for your plant’s health issues. If your soil registers above 7, then it’s considered alkaline.
(You can learn more about what a soil test tells you here).
Step 3: Amend The Soil
There are several ways to decrease your garden’s pH levels and make it more acidic. According to Oregon State’s Extension Service, an easy way to alter acidity is to amend it with elemental sulfur or nitrogen fertilizer.
(You can learn more about which fertilizers are acidic here).
Working elemental sulfur into your garden is the quickest way to make it more acidic. When you mix sulfur with soil, thiobacillius (naturally occurring bacteria) oxidates it and creates sulfuric acid.
Many experts recommend a more gradual approach compared to adding sulfur. Working fertilizer such as ammonium nitrate, urea, ammonium phosphate, or ammonium sulfate into the soil will slowly acidify it over several years. The type you choose will depend on how much of a decrease in pH you need.
It’s important to note that using aluminum sulfate, while effective, carries the risk of side effects that can harm your plants and inhibit growth.
Step 4: Be Patient
Patience is arguably the most difficult gardening-related skill to learn. Any change you make to your soil’s acidity levels could take years to notice an improvement.
In the meantime, continue caring for your garden as you normally would, and observe your plants for any changes.
Conclusion
No matter where you’re located, you shouldn’t have trouble finding an array of plant choices for acidic soil. In many cases, you can even stretch the boundaries of the recommended pH levels as long as you’re providing excellent care otherwise.
You can learn about loam soil (and other soil types) here.
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About the author:
Kathryn is a plant enthusiast and freelance content writer who specializes in home and garden topics. Based in New York, you can get in touch with Kathryn at https://kathrynflegal.journoportfolio.com/.
