An accurate soil test will indicate your soil's pH level will specify the amount of lime or sulfur that is needed to bring it up or down to the appropriate level. 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 strongly acidic soil, while a few (ferns, asparagus) do best in soil that is neutral to slightly alkaline. Acidic (sour) soil is counteracted by applying finely ground limestone, and alkaline (sweet) soil is treated with gypsum (calcium sulfate) or ground sulfur.
| Common Name | Optimum pH Range |
|---|---|
| Trees and Shrubs | |
| Apple | 5.0-6.5 |
| Ash | 6.0-7.5 |
| Azalea | 4.5-6.0 |
| Basswood | 6.0-7.5 |
| Beautybush | 6.0-7.5 |
| Birch | 5.0-6.5 |
| Blackberry | 5.0-6.0 |
| Blueberry | 4.0-6.0 |
| Boxwood | 6.0-7.5 |
| Cherry, sour | 6.0-7.0 |
| Chestnut | 5.0-6.5 |
| Crab apple | 6.0-7.5 |
| Dogwood | 5.0-7.0 |
| Elder, box | 6.0-8.0 |
| Fir, balsam | 5.0-6.0 |
| Fir, Douglas | 6.0-7.0 |
| Hemlock | 5.0-6.0 |
| Hydrangea, blue-flowered | 4.0-5.0 |
| Hydrangea, pink-flowered | 6.0-7.0 |
| Juniper | 5.0-6.0 |
| Laurel, mountain | 4.5-6.0 |
| Lemon | 6.0-7.5 |
| Lilac | 6.0-7.5 |
| Maple, sugar | 6.0-7.5 |
| Oak, white | 5.0-6.5 |
| Orange | 6.0-7.5 |
| Peach | 6.0-7.0 |
| Pear | 6.0-7.5 |
| Pecan | 6.4-8.0 |
| Pine, red | 5.0-6.0 |
| Pine, white | 4.5-6.0 |
| Plum | 6.0-8.0 |
| Raspberry, red | 5.5-7.0 |
| Rhododendron | 4.5-6.0 |
| Spruce | 5.0-6.0 |
| Walnut, black | 6.0-8.0 |
| Willow | 6.0-8.0 |
| Vegetables | |
| Asparagus | 6.0-8.0 |
| Bean, pole | 6.0-7.5 |
| Beet | 6.0-7.5 |
| Broccoli | 6.0-7.0 |
| Brussels sprout | 6.0-7.5 |
| Carrot | 5.5-7.0 |
| Cauliflower | 5.5-7.5 |
| Celery | 5.8-7.0 |
| Chive | 6.0-7.0 |
| Cucumber | 5.5-7.0 |
| Garlic | 5.5-8.0 |
| Kale | 6.0-7.5 |
| Lettuce | 6.0-7.0 |
| Pea, sweet | 6.0-7.5 |
| Pepper, sweet | 5.5-7.0 |
| Potato | 4.8-6.5 |
| Pumpkin | 5.5-7.5 |
| Radish | 6.0-7.0 |
| Spinach | 6.0-7.5 |
| Squash, crookneck | 6.0-7.5 |
| Squash, Hubbard | 5.5-7.0 |
| Tomato | 5.5-7.5 |
| Flowers | |
| Alyssum | 6.0-7.5 |
| Aster, New England | 6.0-8.0 |
| Baby's breath | 6.0-7.0 |
| Bachelor's button | 6.0-7.5 |
| Bee balm | 6.0-7.5 |
| Begonia | 5.5-7.0 |
| Black-eyed Susan | 5.5-7.0 |
| Bleeding heart | 6.0-7.5 |
| Canna | 6.0-8.0 |
| Carnation | 6.0-7.0 |
| Chrysanthemum | 6.0-7.5 |
| Clematis | 5.5-7.0 |
| Coleus | 6.0-7.0 |
| Coneflower, purple | 5.0-7.5 |
| Cosmos | 5.0-8.0 |
| Crocus | 6.0-8.0 |
| Daffodil | 6.0-6.5 |
| Dahlia | 6.0-7.5 |
| Daisy, Shasta | 6.0-8.0 |
| Daylily | 6.0-8.0 |
| Delphinium | 6.0-7.5 |
| Foxglove | 6.0-7.5 |
| Geranium | 6.0-8.0 |
| Gladiolus | 5.0-7.0 |
| Hibiscus | 6.0-8.0 |
| Hollyhock | 6.0-8.0 |
| Hyacinth | 6.5-7.5 |
| Iris, blue flag | 5.0-7.5 |
| Lily-of-the-valley | 4.5-6.0 |
| Lupine | 5.0-6.5 |
| Marigold | 5.5-7.5 |
| Morning glory | 6.0-7.5 |
| Narcissus, trumpet | 5.5-6.5 |
| Nasturtium | 5.5-7.5 |
| Pansy | 5.5-6.5 |
| Peony | 6.0-7.5 |
| Petunia | 6.0-7.5 |
| Phlox, summer | 6.0-8.0 |
| Poppy, oriental | 6.0-7.5 |
| Rose, hybrid tea | 5.5-7.0 |
| Rose, rugosa | 6.0-7.0 |
| Snapdragon | 5.5-7.0 |
| Sunflower | 6.0-7.5 |
| Tulip | 6.0-7.0 |
| Zinnia | 5.5-7.0 |














