bloomstruck hydrangea

Acidic Soil Loving Plants

Water, Sun, and Soil (Nutrients). These are plants three basic needs.

Plants need nutrients and a relationship with elements in the soil can determine the health of plants. Soil pH is important to the uptake of nutrients and related to some common issues that may arise. For example, you may add fertilizer to your garden but still have little effect on your plants if for some reason your soil pH is off.

The texture of the soil is an additional variable (loamy, silty, sandy, or clay) and another topic all together. There is a method at the bottom of the post that will also improve soil texture/aeration.

Now, we will go over acidic soil ranges, what plants grow best in acidic soil, and what you can do to improve your soil’s pH.

What is acidic soil?

The range of pH is from 0-14. Acidic soil is considered anything below 7.

Acidity ranges:
Slight  6.0
Strong  5.5
Very Strong 5.0
Extremely 4.5

Most plants like to grow within the 6-7.5 pH range for optimal nutrient uptake. In Southern MN, you may notice a lot of clay soil with lime, which tends to be more alkaline, 7 or above. Water coming from hoses in this area are usually more basic (increases alkalinity) as well.

Other factors that affect soil acidity are rainfall, nitrogen fertilizers, plants like pines, and subsoil acidity. The best way to know your soil acidity level is a quick home test. We have soil pH tests plus soil nutrient tests. If your plants are thriving than you probably wouldn’t need to test it unless you are curious.

Plants that enjoy acidic soil:

Plants that enjoy slight acidity, 6.0-7.0 range:
Most plants! Each plant has a pH range it can tolerate and many plants can handle 6.0.

Plants that tolerate strong acidity, 5.5:
Trees and shrubs –  Raspberry 5.5-7.0, Pears 5.5-7.0, Peaches 5.5-7.0
Vegetable and Fruits- Potato 5.5, Squash 5.5, Garlic 5.5-8.0, Carrot 5.5-7.0, Sweet Peppers 5.5-7.0, Tomatoes 5.5-7.5, Cauliflower 5.5-7.5, Cucumber, 5.5-7.0, Pumpkin 5.5-7.0, Eggplant 5.5-6.5, Sweet Potatoes 5.2-6.0, Rhubarb 5.5-7.0
Flowers – Begonia 5.5-7.0, Black-Eyed Susan 5.5-7.0, Clematis 5.5-7.0, Marigold 5.5-7.5, Nasturtium 5.5-7.5, Pansy 5.5-6.5, Snapdragon 5.5-7.0, Zinnia 5.5-7.0, Fox Gloves 5.5-6.5, Cyclamen 5.5-6.5

Plants that tolerate very strong acidity, 5.0:
Trees and shrubs – Spruce 5.0-6.0, Juniper 5.0-6.0, Blackberry 5.0-6.0, Apple, 5.0-6.5, Serviceberry 5.0-6.0, Fothergilla 5.0-6.0, Magnolia 5.0-6.0
Fruits – Strawberries 5.5-6.5, Grapes 5.5-7.0
Flowers – Coneflower-Purple 5.0-7.5, Cosmos 5.0-8.0, Gladiolus 5.0-7.0, Lupine 5.0-6.5

Plants that tolerate extremely strong acidity, 4.5:
Trees and shrubs – Azalea 4.5-6, Blueberry 4.5-6, Hydrangea-Blue flowered 4.0-5.0, White Pine 4.5-6.0, Rhododendron 4.5-6
Flowers – Lily-of-the-Valley 4.5-6.0

As you may have noticed, plants have a range of pH that they will grow in and thrive. Those plants that have very strong and an extremely strong acidic soil needs, may need additional amendments to keep soil pH down. If you are noticing any issues like yellowing leaves, no fruit production, growth seems stunted, and not blooming, checking the pH is recommended first before using fertilizers.

What can you do to change soil pH?

The best way to improve soil pH is through addition of amendments and adding organic material. To increase acidity, add sulfur, and to decrease acidity, add lime. With both of these amendments, you will have to do it in stages as to not shock the plant. Read instructions on any product you use since each may differ.

These are our favorite supplements to use to adjust the soil pH and will not shock the plants if used as directed:
Epsoma Soil Acidifer – Organic, Safe, long-lasting, and won’t burn the plants if used as directed. Repeat in 60 day intervals if needed.
Epsoma Berry Tone for Berries – Organic, Good if you need to slightly increase acidity, Use early and late spring, Use on blueberries, strawberries, and raspberries, Will help produce bigger plants and more berries.

Ways to adjust soil pH by adding organic material:
Add compost, manure, and peat moss to your garden beds. If you add compost and manure your soil, it may become more neutral so the addition of peat moss, which is acidic (3.0-4.5) can help temporarily adjust acidity. This is best to do in the fall since it takes more time to adjust the soil pH using this method but feel free to feed plants with top dressing of compost/manure during the growing season which is another great way to improve the soil’s aeration.

Modifying your soil’s pH will take some time. Depending on the type of soil you are working with, the addition of supplements and organic material may be needed year-after-year.

If you test your soil and notice you have troubles with keeping your soil more acidic, choose plants that will tolerate more neutral or alkaline soils. There are plenty out there!