bloomstruck hydrangea

Acidic Soil Loving Plants


Three Plant Needs

Water, Sun, and Soil (Nutrients).

Where does soil pH level come in?

Plants need nutrients and have a balanced relationship with elements in the soil which will contribute to the health of plants.

Plants also have pH level preferences. The soil pH level can affect the uptake of nutrients. Depending on the plant, if the soil pH is not ideal then you may have a stunted and unhealthy plant and it’s not because there isn’t nutrients in the soil.

Put Away the Fertilizer For Now

If you are noticing any issues like yellowing leaves, no fruit production, growth seems stunted, and not blooming, checking the pH is highly recommended first before using fertilizers.

For example, you may add fertilizer to your garden but it still has little effect on your plant health if for some reason your soil pH is off. Too much fertilizer can also inhibit nutrient uptake because of soil nutrient imbalances. In addition, nitrogen and phosphorous runoff is a huge environmental pollutant, especially to our waterways and lakes.

Testing your soil nutrients is good gardening practice and could save you money in the long run. If you know your soil pH is within the proper range and your plant is showing nutrient deficiency symptoms, use a slow release fertilizer (like Bio-tone) for in-ground plants to avoid excessive nutrients and run-off.

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

Many 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 pH or above. Water coming from hoses in this area are usually more basic, which increases soil alkalinity.

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.

Acidic Soil Loving Plants

Plants that prefer slight acidity, 6.0-7.0 range:

Most plants! Each plant has a pH range it can tolerate and many plants can handle down to 6.0.

Plants that prefer 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 prefer 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:
Coneflowers 5.0-7.5, Cosmos 5.0-8.0, Gladiolus 5.0-7.0, Lupine 5.0-6.5

Plants that prefer 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

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.

Changing 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. Add both of these amendments in small stages and increments as to not shock the plant if it’s already planted. Read the instructions on any product you use to properly adjust the pH.

Favorite supplements to adjust the soil pH that 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.

Adjust Soil pH with Organic Matter

Add any type of compost to your garden beds. 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 during the growing season. Reach for compost first when wanting to add nutrients, improving soil aeration, improving water retention, and adjusting pH.

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’re having troubles with keeping your soil more acidic, don’t fight it! Choose plants that will tolerate more neutral or alkaline soils. There are plenty out there!