The main benefit of wood ash in the soil is to raise the soil pH, or make it less acid. Wood ash for agricultural purpose has a calcium carbonate equivalent (CCE) component, which varies from 25-59 percent (Bulletin #2279, Using Wood Ash on Your Farm). Most crops grow best in a slightly acidic soil with a pH between 6.0-6.8. Wood ash is high in calcium content, with the effect of raising soil pH. There’s no point in spreading it around acid-loving plants such as blueberries. The ashes have properties similar to lime products used to raise soil pH. Being alkaline, wood ash obviously isn’t an ideal addition if your soil already has a pH of 7.5 or greater. The process makes lye water. If you boiled off all the water you could use it as the catalyst to make biodiesel, but you'd need more accurate pH measures than those listed below. To contact an expert in your area, visit, or call 888-MSUE4MI (888-678-3464). Raising Soil pH As noted above, wood ash helps buffer acidic soils and can help raise soil pH if that’s needed on your particular plot. Hardwood ash, such as oak or maple, works best, but you can use any type of wood ash. For more information, visit On the plus side, wood ash is prized for its desiccating attribute, which makes it repellent to snails, slugs and soft-bodied insects. pH 10.5) immediately after burn-ing compared with unburned soil. Show your Spartan pride and give the gift of delicious MSU Dairy Store cheese this holiday season! For further information on using wood ash in the garden, contact Dr. Hal Hudson, Michigan State University Extension Horticulture Educator for commercial and consumer vegetable production at 989-672-3870 or If you’ve ever “smothered a fire” at a campsite by shifting ashes over hot coals, you … Every sort of material rototilled or otherwise incorporated into the ground as soil amendment needs to be evaluated for its chemical and physical properties. The chemistry of anything added to the soil depends on its mineral content. Because of the high soil pH in our area, some local gardeners advocate dusting the ground with gypsum — which forms sulfuric acid in contact with water — several times a year to keep their soil pH leaning in a more acidic direction. But they must be used with care, as all that calcium makes them highly alkaline—a range of 9 to 13—and they WILL change your soil's pH. Soils in the pH range of 6.0 to 7.0 is optimal for most lawns and garden plants. Acidic soils (pH less than 5.5) will likely be improved by the addition of Wood Ash. If your soil has a pH level of 6.0 to 6.5, you can use as much as 20 pounds of wood ash without dramatically raising your pH to unmanageable levels. pH Correction of Soil. Wood ash from your fireplace or stove may be used as a soil amendment and fertilizer in the garden. Wood Ash also contains lots of micronutrients, and, on average, 15% calcium—a nutrient often lacking in many of our soils and fertilizers. Lawns prefer a slightly acidic to neutral soil — 6.5 to 7 on the pH scale. Wood ash, when heavily applied, also increases soil salinity that is detrimental to plant growth. Only … The previous two paragraphs are an excerpt from Soil Acidity and Liming Internet Inservice Training, Best Management Practices for Wood Ash Used as an Agricultural Soil Amendment, by Mark Risse, Extension Engineering, 307 Hoke Smith Building, Athens, GA 30602, and Glen Harris, Extension Agronomist, P.O. Does Wood Ash … Details for taking a soil test are available from the Michigan State University Soil and Plant Nutrient Laboratory. There is a history of it being used for many purposes including pottery, food preparation, and in even in soaps. Once the bucket is prepped, start pouring in water. In addition, wood ash contains abundant calcium, an element that elevates soil pH, a negative in our area since native soil pH is usually too high in any case. Ashes even improve the structure and tilth of soils. Gardeners traditionally use it as a good source of potash to ameliorate soil. But his lawn may be a different story. Wood ashes from the fireplace or wood stove may be used to supply both calcium and potassium to soil. >Marshall Maydeck, Arleta Wood ash is composed of many major and minor elements needed by the tree for plant growth. The major component of fresh, white wood-ash is calcite, while K and Na carbonates are present in minor amounts. The CCE tells you how well the wood ash will raise the soil pH compared to lime (calcium carbonate). Wood ash is also useful for pest control. Your email address will not be published. If you really intend to raise the pH level of you’re your soil, you don’t have to wait for limestone and you can use wood ash instead. Wood ash works best if the soil pH level is somewhat acidic, below 6.5. Wood ashes are very alkaline, with pH levels of around 9 to 11. Soil pH of 4.5 to 6.0 is common. But you should do this with precaution of not exaggerating the doses as wood ash increases the pH level. Wood ash is high in calcium content, with the effect of raising soil pH. Make Lye. I always think of an ox when reading about it or hearing its name and for an obvious reason: it’s called oxalis. The combination of the two will determine how the material in question will affect overall soil fertility. Wood ash contains calcium carbonate around 25%, potassium 3% and other useful elements like phosphorous, manganese and zinc. Another important chemical property of soil amendments is pH, a measure of acidity or alkalinity, with 7.0 being neutral. Soil Acidity and Liming Internet Inservice Training, Best Management Practices for Wood Ash Used as an Agricultural Soil Amendment, Remote Learning and Resources for Those at Home During COVID-19 Pandemic. Box 1209, Tifton, GA 31793. Wood ash is particularly useful if you use lots of cattle manure in your garden, as this type of manure is very acidic. Avoid mulching azaleas, which prefer a distinctly acidic pH, with wood ash. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Wood ash is the powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. Learn how your comment data is processed. This information is for educational purposes only. To determine if a garden is a good prospect for wood ash, get a soil test. In addition, wood ash contains abundant calcium, an element that elevates soil pH, a negative in our area since native soil pH is usually too high in any case. The “p” in pH stand for “power”, as in “raised to the power of” in mathematical notation, and the “H” stands for hydrogen. MSU is an affirmative-action, equal-opportunity employer, committed to achieving excellence through a diverse workforce and inclusive culture that encourages all people to reach their full potential. Liming agents are used to increase soil pH (pH is a measure of how acid soil is). Thus, lightly applied in Southern California gardens, wood ash would be useful in pest control but not for increasing soil fertility. Making lye from wood ash. This should fill the bucket almost to the top. Slightly acidic is … While some plants thrive in alkalinity, overly … Wood ash is commonly used as a liming agent because of its high calcium content. Too much ash can increase pH or accumulate high levels of salts that can be harmful to some plants, so use ashes carefully. 3.4K views March 10, 2011. We therefore have a significant amount of wood ash. The salt in the wood ash will kill bothersome pests like snails, slugs and some kinds of soft bodied invertebrates. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Wood Ash as a Liming Agent. Benefits for Soil pH Most wood ash contains a good percentage, about 25 percent, of calcium carbonate, an ingredient in garden lime. Lawn grasses generally prefer slightly acidic soil in the 6.0 to 7.0 pH range, but high-nitrogen fertilizers tend to lower soil pH over time. Wood ash provides potassium which is essential for fruit crops Where Not to Use Wood Ash in the Garden. Any type of problem soil, whether hard and poorly drained or overly sandy, will benefit from the addition of these materials. Test your soil using an inexpensive test kit if you don’t already know its pH. In terms of commercial fertilizer, average wood ash would probably be about 0-1-3 (N-P-K). There is a certain plant that has remarkable strength. Bob has limited uses for wood ashes in his garden. N. Nashville Member. Soil pH is a measure of acidity on a 14 point scale, with 7 being neutral. The physical properties of materials such as peat moss, perlite, nitrolyzed redwood shavings, straw and compost increase soil fertility by making the soil spongier. Wood ash is not recommended for use with garden soils that have a pH greater than 6.5, or when the soil test potassium level is very high. If you have acidic soil, you can use wood ash to reduce the acidity. It is recommended that garden soil be tested every two to three years to determine current nutrient levels and to make nutrient adjustments accordingly. Soil pH is a measure of the soils relative acidity or alkalinity. Acidic soil amendments, such as peat moss, may have a pH as low as 3.5.