Soil pH Levels for Plants: Find Out What pH is Best for Your Garden

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Optimum Soil pH Levels for Trees, Shrubs, Vegetables, and Flowers

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What is your garden soil’s pH level? Every plant prefers a different level of acidity. Use this soil pH chart to find out which pH level is best for your garden plants. Then, learn how to adjust it accordingly!

The Secret of Soil pH

Having the right soil pH is key to growing a healthy garden, but it’s a factor that’s often overlooked in favor of nutrient levels and soil consistency. While these are also crucial things to consider, the pH of the soil plays a major role in how well your plants can absorb the nutrients you provide them, so it’s important to get it right!

The wrong pH often won’t kill plants outright, but it can affect their growth and result in subpar blooms or crops, depending on how sensitive the plant is. In actuality, many plants are able to adapt to a range of pH levels. Hydrangeas, for example, produce different colored flowers depending on whether they’re grown in acidic or alkaline soil.

A pH of 6.5 is just about right for most home gardens, since most plants thrive in the 6.0 to 7.0 (slightly acidic to neutral) range. Some plants (blueberries, azaleas) prefer more acidic soil, while a few (ferns, asparagus) do best in soil that is neutral to slightly alkaline.

How do you find out your soil pH? To do a simple pH test, you can acquire a soil pH test kit online or from a local garden store. However, for a similar cost (or even for free), you may be able to have your soil tested by your state Cooperative Extension, which can provide a much more in-depth analysis of your soil (including nutrient levels and other helpful bits of information). 

How Do You Adjust Soil pH?

Once you figure out your soil pH, it may be necessary to adjust it to suit the needs of the plants you’re growing. The level of acidity will specify the amount of soil amendment that is needed to bring it up or down to the appropriate level. Acidic (“sour”) soil is counteracted by applying finely ground limestone or wood ash, and alkaline (“sweet”) soil is typically treated with gypsum (calcium sulfate), ground sulfur, or compost.

Read more about preparing soil for planting.

Optimum Soil pH Levels for Plants

Common NameOptimum pH Range
Trees and Shrubs
Vegetables
Flowers
Apple5.0-6.5
Ash6.0-7.5
Azalea4.5-6.0
Basswood6.0-7.5
Beautyberry Shrub6.0-7.5
Birch5.0-6.5
Blackberry5.0-6.0
Blueberry4.0-6.0
Boxwood6.0-7.5
Cherry, sour6.0-7.0
Chestnut5.0-6.5
Crab apple6.0-7.5
Dogwood5.0-7.0
Elder, box6.0-8.0
Fir, balsam5.0-6.0
Fir, Douglas6.0-7.0
Hemlock5.0-6.0
Hydrangea, blue-flowered4.0-5.0
Hydrangea, pink-flowered6.0-7.0
Juniper5.0-6.0
Laurel, mountain4.5-6.0
Lemon6.0-7.5
Lilac6.0-7.5
Maple, sugar6.0-7.5
Oak, white5.0-6.5
Orange6.0-7.5
Peach6.0-7.0
Pear6.0-7.5
Pecan6.4-8.0
Pine, red5.0-6.0
Pine, white4.5-6.0
Plum6.0-8.0
Raspberry, red5.5-7.0
Rhododendron4.5-6.0
Spruce5.0-6.0
Walnut, black6.0-8.0
Willow6.0-8.0
Asparagus6.0-8.0
Bean, pole6.0-7.5
Beet6.0-7.5
Broccoli6.0-7.0
Brussels sprout6.0-7.5
Cabbage6.0-7.0
Carrot5.5-7.0
Cauliflower5.5-7.5
Celery5.8-7.0
Chive6.0-7.0
Cucumber5.5-7.0
Garlic5.5-8.0
Kale6.0-7.5
Lettuce6.0-7.0
Pea, sweet6.0-7.5
Pepper, sweet5.5-7.0
Potato4.8-6.5
Pumpkin5.5-7.5
Radish6.0-7.0
Spinach6.0-7.5
Squash, crookneck6.0-7.5
Squash, Hubbard5.5-7.0
Tomato5.5-7.5
Alyssum6.0-7.5
Aster, New England6.0-8.0
Baby’s breath6.0-7.0
Bachelor’s button6.0-7.5
Bee balm6.0-7.5
Begonia5.5-7.0
Black-eyed Susan5.5-7.0
Bleeding heart6.0-7.5
Canna6.0-8.0
Carnation6.0-7.0
Chrysanthemum6.0-7.5
Clematis5.5-7.0
Coleus6.0-7.0
Coneflower, purple5.0-7.5
Cosmos5.0-8.0
Crocus6.0-8.0
Daffodil6.0-6.5
Dahlia6.0-7.5
Daisy, Shasta6.0-8.0
Daylily6.0-8.0
Delphinium6.0-7.5
Foxglove6.0-7.5
Geranium6.0-8.0
Gladiolus5.0-7.0
Hibiscus6.0-8.0
Hollyhock6.0-8.0
Hyacinth6.5-7.5
Iris, blue flag5.0-7.5
Lily-of-the-valley4.5-6.0
Lupine5.0-6.5
Marigold5.5-7.5
Morning glory6.0-7.5
Narcissus, trumpet5.5-6.5
Nasturtium5.5-7.5
Pansy5.5-6.5
Peony6.0-7.5
Petunia5.5-6.0
Phlox, summer6.0-8.0
Poppy, oriental6.0-7.5
Rose, hybrid tea5.5-7.0
Rose, rugosa6.0-7.0
Snapdragon5.5-7.0
Sunflower6.0-7.5
Tulip6.0-7.0
Zinnia5.5-7.0

Learn more about testing your garden’s soil.

About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann