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Vegetable Crop Soil pH Tolerances

Cabbage family crops that share similar soil pH requirements growing together.
Cabbage family crops that share similar soil pH requirements growing together.
Cabbage family crops that share similar soil pH requirements growing together.

Vegetables and other plants grow best when the soil pH is optimal for the plants being grown. It is important to match a plant to the soil pH or to adjust the soil pH to a plant’s needs.

Soil pH is the measure of the soil’s acidity or alkalinity. Soil acidity and alkalinity is measured on a scale of 0 to 14, called the pH scale. Most plants grow between the pH range of 4.5 to 8.0; a soil pH of 5.0 has a high acid content; a soil pH of 7.5 has a high alkaline content; a soil pH of 7.0 is neutral. A soil pH test will determine a soil’s pH.

Soil pH is important because a soil’s acidity or alkalinity determines what plant nutrients are available to plant roots. Nutrients in the soil—elements such as nitrogen, phosphorus, and potassium—become available to plants when they dissolve in water or soil moisture. Most plant nutrients will not dissolve when the soil is either too acidic or too alkaline.

Knowing the soil pH in the planting beds in your garden will allow you to group plants by their pH needs. Grow together plants with like pH needs, similar temperature tolerances, and nutritional needs.

Crops Listed by Soil pH Requirements:

This list will allow you to group plants according to their soil pH tolerances. You will find that in the lists below, some plants may be repeated if they have a wide soil pH range tolerance; that is some plants will grow equally well in acid or alkaline soil.

Acid Soil Crops: The following crops prefer a pH of 4 to 5.5:

  • Blackberry (5.0-6.0)
  • Blueberry (4.5-5.0)
  • Cranberry (4.0-5.5)
  • Parsley (5.0-7.0)
  • Peanut (5.0-7.5)
  • Potato (4.5-6.0)
  • Raspberry (5.5-6.5)
  • Sweet potato (5.5-6.0)

 

Somewhat Acid Soil Crops: The following crops prefer require a somewhat acid soil; they can tolerate a pH of 5.5 to 6.5:

  • Apple (5.0-6.5)
  • Basil (5.5-6.5)
  • Carrot (5.5-7.0)
  • Cauliflower (5.5-7.5)
  • Chervil (6.0-6.7)
  • Corn (5.5-7.5.)
  • Cucumber (5.5-7.0)
  • Dill (5.5-6.5)
  • Eggplant (5.5-6.5)
  • Garlic (5.5-7.5)
  • Melon (5.5-6.5)
  • Parsley (5.0-7.0)
  • Pepper (5.5-7.0)
  • Pumpkin (6.0-6.5)
  • Radicchio (6.0-6.7)
  • Radish (6.0-7.0)
  • Rhubarb (5.5-7.0)
  • Sorrel (5.5-6.0)
  • Squash, winter (5.5-7.0)
  • Sweet potato (5.5-6.0)
  • Tomato (5.5-7.5)
  • Turnip (5.5-7.0)

 

Moderately Alkaline Soil Plants: The following crops will tolerate a pH of 6.0 to 7.0 or greater:

  • Artichoke (6.5-7.5)
  • Arugula (6.5-7.5)
  • Asparagus (6.0-8.0)
  • Bean, pole (6.0-7.5)
  • Bean, lima (6.0-7.0)
  • Beet (6.0-7.5)
  • Broccoli (6.0-7.0)
  • Broccoli rabe (6.5-7.5)
  • Brussels sprouts (6.0-7.5)
  • Cabbage (6.0-7.5)
  • Cantaloupe (6.0-7.5)
  • Cauliflower (6.0-7.5)
  • Celery (6.0-7.0)
  • Chinese cabbage (6.0-7.5)
  • Celeriac (6.0-7.0)
  • Celery (6.0-7.0)
  • Chinese cabbage (6.0-7.5)
  • Chive (6.0-7.0)
  • Cilantro (6.0-6.7)
  • Claytonia (6.5-7.0)
  • Collard (6.5-7.5)
  • Cress (6.0-7.0)
  • Endive/escarole (6.0-7.0)
  • Fennel (6.0-6.7)
  • Gourd (6.5-7.5)
  • Horseradish (6.0-7.0)
  • Jerusalem Artichoke/Sunchoke (6.7-7.0)
  • Kale (6.0-7.5)
  • Kohlrabi (6.0-7.5)
  • Leek (6.0-8.0)
  • Lettuce (6.0-7.0)
  • Marjoram (6.0-8.0)
  • Mizuna (6.5-7.0)
  • Mustard (6.0-7.5)
  • Okra (6.0-7.5)
  • Onion (6.0-7.0)
  • Oregano (6.0-7.0)
  • Pak choi (6.5-7.0)
  • Parsnip (5.5-7.5)
  • Pea (6.0-7.5)
  • Radicchio (6.0-6.7)
  • Radish (6.0-7.0)
  • Rhubarb (6.5-7.0)
  • Sage (6.0-6.7)
  • Salsify (6.0-7.5)
  • Spinach (6.0-7.5)
  • Squash, summer (6.0-7.0)
  • Sunflower (6.0-7.5)
  • Sunflower (6.0-7.5)
  • Swiss chard (6.0-7.5)
  • Tarragon (6.0-7.5)
  • Tomatillo (6.7-7.3)
  • Watermelon (6.0-7.0)

 

Very Acid to Alkaline Soil Tolerant Plants: The following crops have the greatest tolerance for a wide range of soil acidity or alkalinity, from about 5.0 to 7.0:

  • Alpine strawberry (5.0-7.5)
  • Carrot (5.5-7.0)
  • Cauliflower (5.5-7.5)
  • Corn (5.5-7.5)
  • Cucumber (5.5-7.0)
  • Dill (5.5-6.7)
  • Endive/Escarole (5.8-7.0)
  • Garlic (5.5-7.5)
  • Parsley (5.0-7.0)
  • Parsnip (5.5-7.5)
  • Peanut (5.0-6.5)
  • Pepper (5.5-7.0)
  • Rutabaga (5.5-7.0)
  • Squash, winter (5.5-7.0)
  • Tomato (5.5-7.5)
  • Turnip (5.5-7.0)

 

Click on These Related Articles on Soil pH:

Understanding Soil pH

How to Test Your Soil

Adjusting Soil pH

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53 Comments

  1. I don’t see any pH ranges that include alkaline soils. All of the “tolerances” are below neutral… Acidic soils. So what plants can tolerate a pH of 7.8… 8.0 or even 8.5?

    • You are unlikely to have great success trying to grow vegetables in highly alkaline soil. Soil pH effects the ability of plants to take up nutrients in the soil. The higher and lower the pH the more difficult it becomes for plants to claim the nitrogen, phosphorus, and potassium–and other elements–in the soil. If your soil pH is high, try growing some of the crops listed for moderate to high pH and keep a record of the success. The success of vegetables in high pH is constantly being studied by research agronomists.

      • I have been gardening in the same spot for 40 years with tremendous yields. My soil is extremely high in fertility without ever using any artificial fertilizers. My ph runs between 7.5 and 7.8 depending on which lot. According to all of the stats I should have poor results. I give bushels of tomatoes away, as well as winter squash . The only thing I ever have trouble growing is watermelon. My soil is tested professionally about every 3 years.

        • That’s strange. I have grown watermelon in alkaline soil without any problems. It might depend on the cultivar your growing. Some can be easy such as Sugar Baby and Crimson Sweet. Some can be difficult such as Sangria.
          Of course I amend my soil. I have grown watermelon in call desert soil without amendments. Watermelon is has been easy for me to grow. I don’t really fertilize. Fertilizer is too expensive. It only speeds up the process of watermelon growth. It takes two months to harvest a watermelon.
          Some crops I do struggle with are strawberries and tomatoes. Usually they develop too early. I have amended soil for these crops. But I blame my desert heat.
          I live in Phoenix, Arizona. The scalding sun kills my crops sometimes. The lazy are the unfortunate. I water my plants every morning and evening and set up some shade cloth in my raised bed near my cactus garden.
          Although, I should really set up an irrigation system so I won’t need to worry about my watering schedule. But I’m damned. Water in Phoenix is so expensive. That’s why many have reported to water conservative gardens and xeriscaping. Everything looks nicer with some water.

    • You can get a pH meter or a pH test kit at a nearby garden center or nursery or online. Most kits come with directions for testing pH and suggestions for amending the soil.

  2. When you state things like Beans, carrots, watermelon is the PH across the board with all varieties or do they vary in PH requirements? Thanks

    • Your question has a complicated answer: The pH scale ranges from 0 to 14 with 7 being a neutral pH. The low end of the scale represents high acidity; the high end represents alkalinity. High levels of either acidity or alkalinity can kill plants and microorganisms in the soil. High acidity in the soil can leave plants unable to absorb ground water needed for growth. In very extreme situations, this could leave herbivores without a food source. Acidic water can harm aquatic plant life, a food source for fish. Acid rain adds aluminum to the soil and can affect plant nutrients in the soil. Acidic water can inhibit sodium in the blood and oxygen in the tissues of fish. Acidic water can also affect the functioning of fish gills. Some fish species tolerate acidic water better than others. Brook trout tolerate water with a pH as low as 5.0 while small mouth bass feel the effects at a pH of 6.0. Low water acidity can stress or stunt the growth of some fish making them less able to compete for food. If you are simply lowering the pH of your garden soil by a point or two, animals will not be harmed.

  3. Hi Steve, I was mystified at the pitiful potato harvest I had. The end product was potatoes that simply wouldn’t cook. I Googled but found little to indicate what was wrong. It has only recently occurred to me that much of my problem is that the garden soil is right next to concrete blocks, which will be alkaline. Does this make sense to you? Unfortunately, other plants I’ve been growing there (daphne, blueberry) also have acidic preferences and are not particularly happy. The rhubarb on the other hand seems ecstatic.

    • Chemical residue from the manufacture of the concrete blocks may have contaminated the soil. A soil pH test will tell you if the soil is too alkaline. Potatoes prefer a soil pH in the range of 5.0 to 6.8; a soil test by a professional lab can also tell you what other chemicals may be in the the soil. In the meantime, plant edibles in a different part of the garden or in containers.

    • Your soil is quite alkaline; you should attempt to lower the pH. Add as much aged compost or commercial organic planting mix as possible.
      See this link: https://harvesttotable.com/adjusting-soil-ph/
      Here are vegetables that can tolerate alkaline soil–but your soil is high in alkalinity:
      Vegetables for Alkaline Soils
      Asparagus (6.0-8.0)
      Beans, pole (6.0-7.5)
      Beet (6.0-7.5)
      Brussels Sprouts (6.0-7.5)
      Cauliflower (5.5-7.5)
      Garlic (5.5-8.0)
      Kale (6.0-7.5)
      Pea, sweat (6.0-7.5)
      Pumpkin (5.5-7.5)
      Spinach (6.0-7.5)
      Crookneck Squash (6.0-7.5)
      Tomato (5.5-7.5)

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