Alkaline soils are difficult. They have a chalky texture,\nwhich makes them hard to work, and creates an unhealthy soil structure. They\nmake up the majority of the soils in U.S. deserts, which shows how frustrating\nthey can be to manage.\n\n\n\nIf you have alkaline soil on your property, don\u2019t despair. It can be managed but, where do you start? \n\n\n\nHow to correct alkaline soil? Alkaline soil can be managed with consistent applications of compost, which helps plants adapt to higher pH levels. DIY pH tests can help identify alkaline soils, and local nurseries can help you find plants that tolerate high pH levels in your climate zone.\n\n\n\nWe\u2019ve put together an in-depth review of the science behind pH values to help you understand why high pH causes so many problems.\n\n\n\nDon\u2019t care about the science? That\u2019s fine. Jump to the section you want to learn about:\n\n\n\nHow Does pH Affect Soil?What Makes A Soil Alkaline?How to test your soil's pHSolutions for alkaline soilsPlants that tolerate high pH \n\n\n\nWhat Is pH?\n\n\n\nIn short, pH is a scale that represents the acidity or\nbasicity (alkalinity) of a substance. \n\n\n\nThe acronym pH stands for power of hydrogen, or,\naccording to some sources, percentage of hydrogen. This percentage is\nrepresented on a scale of 0-14, with 7 as neutral.\n\n\n\nWater is composed of hydrogen and oxygen, but certain\nsubstances can break or change the bonds between the H and O atoms, and cause\nhydrogen ions to form.\n\n\n\nWhen a hydrogen atom breaks off and joins a water molecule,\ntwo new molecules are formed. The water molecule that lost a hydrogen atom\nbecomes OH- (hydroxide), and the water molecule that added a\nhydrogen atom becomes H3O+ (hydronium). (source)\n\n\n\nWhen there is an even number of hydroxide and hydronium, the\npower of hydrogen (pH) is neutral. When hydroxide ions (OH-)\noutnumber hydronium ions (H3O+), the pH is acidic. When\nhydronium ions (H3O+) outnumber hydroxide ions (OH-),\nthe pH is basic, or alkaline.\n\n\n\nPure, distilled water has a pH of 7, which makes it\nperfectly neutral. One of the most extreme acids, battery acid, has a pH of 0,\nwhile an equally-destructive chemical, drain cleaner, has a pH of 14.\n\n\n\nAcidity and alkalinity determine whether or not certain enzymes can function. Within a person\u2019s digestive system, different enzymes digest different types of foods. Stomach acid allows certain enzymes to work, whereas the large intestine has a different pH, which allows different enzymes to work. Each enzyme has an ideal pH range to operate within, and each enzyme will denature, or fall apart, outside of that pH range.\n\n\n\nEnzymes are responsible for performing certain chemical processes within living organisms. Therefore, the pH of what goes into an organism, and the pH of the surrounding substances, will affect the chemical processes that support that organism.\n\n\n\nHow Does pH Affect Soil?\n\n\n\nSoil is an ecosystem. Within that ecosystem, micro and macro\norganisms work to break down organic material into forms that plants can absorb\nand use for growth.\n\n\n\nNitrogen is the most important nutrient for plant growth, but plants don\u2019t actually absorb nitrogen. \n\n\n\nEnzymes within the soil latch on to nitrogen (N2) and transform it into ammonia (NH3) through a process known as nitrogen-fixing. (source) This process changes an inert form of nitrogen into a form that plants can absorb and use for growth. \n\n\n\nNo matter what form of fertilizer you apply to your lawn or\ngarden, you are never actually feeding plants. You are adding nitrogen to the\nsoil, and then relying on the enzymes within the soil to transform it into\nnutrients that your plants will use. \n\n\n\nThere are hundreds of enzymes involved in transforming inert\nvitamins and minerals into forms that your plants can absorb and use. Each\nenzyme has an ideal pH range to perform this process, and each enzyme will\ndenature outside of this range.\n\n\n\nFor plants, the ideal pH range is 6.0-6.5, or slightly acidic. \n\n\n\nToo acidic, and the enzymes that transform many key\nnutrients begin to decrease, causing deficiencies. At the same time, enzymes\nthat transform trace minerals are more active, causing mineral toxicities.\n\n\n\nToo alkaline, and the enzymes that transform minerals are less active, causing iron and mineral deficiencies. Extremely alkaline soils (8.5 pH) denature the enzymes that transform key minerals, causing deficiencies in nitrogen, phosphorus, calcium, and magnesium. (source)\n\n\n\nSoil structure is also affected by pH values. \n\n\n\nThe enzymes that break down organic material operate best\nwithin a pH range of 5-8, but severely acidic or alkaline soils break down\nthese enzymes, which brings decomposition to a halt. \n\n\n\nThe decomposition process is what turns organic material\ninto organic matter; a huge influencer on soil structure. When organic material\nis unable to decompose, the soil structure is compromised and can become\ncompacted and form thick, impenetrable layers.\n\n\n\nSoil aggregates, or clods, are held together by the\ncation-exchange capacity (CEC) of elements within the soil. Certain elements\nare attracted to each other, which helps soil hold its shape. \n\n\n\nClay soils generally have a higher CEC, which causes it to form strong aggregates. This strong bond is aided by a higher pH value, which means generally, clay soils have a higher pH, and are slightly alkaline.\n\n\n\nBut this can vary depending on region. A simple and inexpensive soil test (link to Amazon) will provide definitive answers specific to your area.\n\n\n\nSandy soils tend to have a lower CEC, which causes it to be\ngrainy and prone to erosion. This lack of a bond is partly due to a low pH\nvalue, which means generally, sandy soils have a low pH, and are slightly\nacidic.\n\n\n\nThere are many different factors that affect pH, and only a few are within our control. Some soils would require so much intervention that it\u2019s nearly impossible to alter the pH values. For these soils, it is more practical to find plants that tolerate pH extremes and work on slowly improving the soil quality.\n\n\n\nWhat Makes A Soil Alkaline?\n\n\n\nSoil may be alkaline for a few different reasons.\n\n\n\nWater\n\n\n\nPure water has a pH of 7, but most water sources are a\nproduct of the surrounding environment. Therefore, the pH of water will vary by\nregion. \n\n\n\nWhen water picks up minerals, it becomes more alkaline.\nCommon sources of alkaline water are natural springs, mountain runoff, or water\nthat passes through limestone or over and through other rock formations.\n\n\n\nUsing alkaline water to irrigate your lawn or garden can\ninfluence the pH of the soil, but not drastically. \n\n\n\nWater is generally alkaline because the surrounding\ntopography is alkaline. So, alkaline water is the result of alkaline soil. Chances\nare, it\u2019s your soil that\u2019s causing a rise in the pH of the water, and not the\nother way around.\n\n\n\nCommercial Irrigation\n\n\n\nThis is the exception to water\u2019s influence on pH values. If\nyou live in a rural area near farms, the water may be alkaline due to modern\nfarming practices.\n\n\n\nIn natural settings, plant material dies and is returned to the soil as organic matter, which helps maintain a slightly acidic pH value. In large-scale farming operations, crops take in the soil\u2019s resources, but then the plant material is removed, which leaves the soil deficient in many nutrients and minerals. (source)\n\n\n\nThis causes a chain reaction that results in low pH, which\nfarmers then try to remedy by adding lime. \n\n\n\nLime helps to raise pH, for a time, which allows farmers to\ngrow another crop without the negative effects of acidic soil.\n\n\n\nAs farmers irrigate, this lime is leached down into the\ngroundwater, which is then passed on to the water supply of rural areas. When\nyou use this water on your lawn or veggie garden, your slightly-acidic soil gets\na small dose of lime. Over time, lime buildup can cause alkaline soil, even\nthough your soil is naturally acidic.\n\n\n\nParent Material\n\n\n\nThe foundation of any soil structure is the parent material.\nAll soils have particles of clay, silt, and sand that were deposited by wind,\nwater, or natural weathering of the surrounding environment.\n\n\n\nIf the parent material of a soil is calcic, the resulting\nsoil will have large amounts of calcium carbonate. This is the main ingredient\nin chalk, and also the main component of lime. \n\n\n\nSoils with a calcic parent material have chalky, clay\ntextures, and can form thick layers of concrete within the soil. This type of\nsoil is most common in dry, arid regions of the Western United States.\n\n\n\nHow Do I Test My Soil\u2019s pH?\n\n\n\n\n\n\n\nHomeowners have a variety of options for pH tests. Tests\nrange from a ballpark guesstimate to an incredibly accurate analysis. The test\nyou choose will be determined by what you are growing, and how much work you\nwant to do to improve your soil.\n\n\n\nBallpark Guesstimate\n\n\n\nThere are few layman\u2019s tests to determine soil pH, and these\nare best for the casual gardener or as a diagnostic tool for soil issues.\n\n\n\nIf you\u2019ve noticed yellow leaves, curling leaves, purple\nstems, or other plant deformities, you may have a pH imbalance. This can be\nconfirmed by a DIY soil test that can help you determine a plan of action.\n\n\n\nBaking Soda & Vinegar\n\n\n\nBaking soda is alkaline, and vinegar is acidic. Acids and\nbases react with solutions with an opposite pH value. This is why vinegar and\nbaking soda foam when they are mixed together.\n\n\n\nTake two small cups and a bottle of distilled (not tap)\nwater out to the area of soil you want to test. Dig a hole about 4\u201d deep, and\nremove organic debris and rocks. Fill the cup about halfway with soil, and add\nenough distilled water to make a muddy solution.\n\n\n\nNext, add a few ounces of vinegar. If the soil foams or\nfizzes, your soil is alkaline.\n\n\n\nIf the mixture doesn\u2019t fizz, repeat the process, but add\nbaking soda instead of vinegar. If the mixture fizzes, your soil is acidic.\n\n\n\nThe more pronounced the reaction, the more extreme the pH\nvalue. Most plants want a slightly acidic soil, so a light amount of fizzing\nafter the baking soda indicates your pH is right where it needs to be. \n\n\n\nRed Cabbage\n\n\n\nOn the off-chance you have a red cabbage in your\nrefrigerator, you can make an easy pH test with a few pots and some distilled\nwater.\n\n\n\nBring distilled (not tap) water to a boil. Chop up\nthe cabbage, and boil until the water turns a deep purple color. Discard the\ncabbage, and pour a small amount into two containers.\n\n\n\nAdd a splash of vinegar to one container, and a dash of baking soda to the other. One should turn pink, and the other should turn bluish-green.\n\n\n\nIf the two solutions change color, this indicates you have successfully\ncreated a pH indicator from a cabbage. You\u2019re awesome.\n\n\n\nNext, collect a sample of soil from the area you wish to\ntest. Put a spoonful of soil in a clean container, and add the cabbage solution\nwhile stirring. Wait for the solution to change colors.\n\n\n\nIf the liquid turns pink, it means your soil is acidic.\nBluish green liquid means your soil is alkaline. The more drastic the color\nchange, the more extreme the pH value. A slightly pink liquid means your soil\nhas a healthy pH range.\n\n\n\nMore Accurate pH Tests\n\n\n\npH Strips\n\n\n\nSoil pH strips are simple to use, cheap, and deliver a much\nmore useful result. While vinegar and baking soda can tell you whether soil is\nacidic or alkaline, pH strips can give a more accurate representation of the pH\nof your soil. This is helpful if you garden consistently, or have recurring\nproblems with your lawn and landscape.\n\n\n\nTests are readily available in most hardware stores, local\ngreenhouses, lawn & garden stores, and online. \n\n\n\nWhile instructions will vary, most kits will have you mix\nenough water and soil together to make the texture of a milkshake. Then, dip a\ntest strip into the mixture for about 30 seconds. Dip the strip in distilled\nwater to clean off the mud, and look at the color to determine the pH value. \n\n\n\nPinks and yellows indicate acidic soils, while greenish browns indicate alkaline soils. The colors will depend on the test strips, but you should be able to determine a numerical value for the pH range.\n\n\n\nIncredibly Accurate pH Tests\n\n\n\npH Meters\n\n\n\nMeters are more common in commercial production when large amounts of tests are performed on a regular basis. However, if you have persistent pH issues, or you\u2019re trying to improve a difficult soil, this may be worth the investment. \n\n\n\nMeters range from $10-$1,000, but most homeowners only need\na simple, inexpensive instrument.\n\n\n\nMeters will need to be calibrated with a buffing solution before use, and instructions vary widely depending on which meter you choose. Results will be very accurate and can help you track progress if you are working on a long-term soil improvement plan.\n\n\n\nLocal Extension Office\n\n\n\nMost local extension offices offer simple soil testing\nservices. If you plan on growing plants for a hobby business, or if you are\nbattling difficult soil conditions, ask your local agent how to get a soil\nanalysis.\n\n\n\nYou will likely need to take your own soil samples from multiples locations on your property, and send them into a local university for testing. This analysis will give you an in-depth report on your soil, including pH, available nutrients, organic matter, and structure.\n\n\n\nHow Do I Lower My Soil\u2019s pH?\n\n\n\nAlkaline soil will have many negative characteristics, but\nthe solution for all of them is the addition of organic matter. \n\n\n\nCompost doesn\u2019t technically lower pH, but it does act as\na buffer so soil can operate as if it were more acidic. Over time, compost\nwill act as a conditioner that lessens the effects of alkaline soil, and\nimproves nutrient availability and enzyme activity.\n\n\n\nThe downside is that you will need a lot of\ncompost. A soil with a pH over 8 will need a 4\u201d layer of compost consistently\nmixed in each year. A large influx of organic matter can actually lower the\navailability of nitrogen in the soil, so while soil conditions will improve,\nyou may see signs of nitrogen deficiency for a few months after application.\n\n\n\nCompost also provides the ideal habitat for soil microorganisms, which help improve all aspects of soil life. The texture of compost improves the structure, and the soil\u2019s ability to hold or drain water. \n\n\n\nElemental sulfur and ammonium sulfate can also lower pH, but this will have a drastic effect on pH values. If you are battling extremely alkaline soils, sulfuric amendments will dramatically lower the pH value over the course of a year. (source)\n\n\n\nHowever, with this drastic change comes the potential for\ndoing serious damage. Without the proper application rate, too much sulfur will\ncause extremely acidic soils that are in worse condition than the original soil\nprofile. Sulfuric amendments are best used in conjunction with a local expert\nwho can read a soil analysis and recommend a specific application rate for your\nsoil.\n\n\n\nBoth compost and sulfuric amendments can be used together to\nimprove alkaline soils. Compost will act as a buffer that helps create a\nhealthier overall soil structure, while amendments can help to make your soil\nimmediately able to grow plants that would suffer in alkaline conditions.\n\n\n\nPine needles, coffee grounds, and peat moss can also\nlower pH, but are best suited for mulching small areas at the base of\nestablished plants. These materials are effective at lowering pH, but\ndifficult to use on a large scale. There aren\u2019t many companies that sell used\ncoffee grounds by the truckload.\n\n\n\nInstead, use these materials sparingly and as they become available. Dump your used morning coffee grounds around the base of a tree, rake up pine needles and mix them into your compost pile, and incorporate peat moss into your mulch for a mild pH reduction.\n\n\n\nWhat Plants Tolerate Alkaline Soil?\n\n\n\nMost plants prefer slightly acidic soil, so while few thrive\nin alkaline conditions, many will tolerate them. \n\n\n\nTrees\n\n\n\nTrees are incredibly resilient, and many tolerate a wide\nvariety of soil conditions. However, if you are installing a new landscape on\nalkaline soil, there are some trees that will perform better than others:\n\n\n\nRedbudElmsLindensKatsura treeHophornbeamYellowwoodBuckeyeIronwoodHackberrySilver Maple\n\n\n\nShrubs\n\n\n\nThere are many shrubs that do well in alkaline soils, and\nmany of the ones listed below have beautiful blooms and foliage to add interest\nto your landscape:\n\n\n\nHydrangeaBoxwoodWeigelaOleanderBeauty BushLilacsChokeberryCotoneasterSmoke BushBarberrySpireaForsythia\n\n\n\nPerennials\n\n\n\nPerennials can be more picky about soil conditions, but\nthere are still a wide variety that tolerate alkaline soils:\n\n\n\nNew England AsterBigroot GeraniumYarrowClematisCampanulaCockscombHostaPhloxDianthusShasta DaisyDaylilyAstilbeCinquefoil\n\n\n\nFruits\n\n\n\nThere aren\u2019t many fruits that tolerate alkaline conditions.\nMost prefer acidic soils, but there are still a few that will do well:\n\n\n\nCantaloupeNectarinesPeachesWatermelon\n\n\n\nHerbs\/Vegetables\n\n\n\nMany vegetables tolerate alkaline soils, so, if in doubt,\nplant them and adjust as needed:\n\n\n\nOreganoAsparagusCabbageCeleryPeasTomatilloArtichokeArugulaBeansThymeParsleyOkraSweet PotatoChivesCilantroEndiveKaleMintLettuceOnionRadishSage\n\n\n\nThere are many other alkaline-tolerant plants, but it is\nbest to visit a local nursery to see which plants will do well in your climate\nzone as well as soil conditions.\n\n\n\nAlkaline soil is a difficult challenge, but it can be\nmanaged with consistent applications of compost and by installing plants that\ntolerate a high pH value.\n\n\n\nSoils with a high pH also have issues with compaction, overwatering,\nand nutrient deficiencies. Read our articles on soil management for more advice\non managing difficult soil profiles.\n\n\n\nRelated Questions\n\n\n\nHow do I fix acidic soil?\n\n\n\nAlmost all soil problems can be fixed with the addition of compost. Organic matter improves all soil properties and acts as a conditioner that buffers the pH value of a soil. Add 2\u201d-4\u201d of compost each year until pH values are close to 6.5.\n\n\n\nHow accurate are pH tests?\n\n\n\nHome tests are only accurate for determining whether your\nsoil is acidic or alkaline. Test strips are accurate, but can be difficult to\ninterpret. The pH meters are generally accurate as long as they are calibrated\nproperly, and third-party analysis provides the best overview of the health of\nyour soil.