Is Wood Ash Good For Grass

Is Wood Ash Good for Grass?


What’s your secret to a lovely, green lawn?

Do you use fertilizer, organic plant food or do you have a special technique to keep grass greener and livelier?

Some owners swear that wood ash is perfect for growing thick and greener grass. There is something in wood ash that makes it perfect for growing healthy plants, especially grass.

This guide will help you discover the power of wood ash for grass and all other garden plants.

Why is wood ash perfect for grass?

Wood ash is good for grass simply because it is from plant material. This substance contains around 13 essential nutrients that soil has for optimum plant growth.

Expert OSU Extension soil scientist Dan Sullivan explains that these 13 nutrients can boost plant growth and can improve overall plant health. He explains: “When wood burns, nitrogen and sulfur are lost as gas,” Sullivan said, “but calcium, potassium, magnesium, and other trace elements remain. The carbonates and oxides in the ash are valuable liming agents that can raise pH and help neutralize acid soils.”

The nutritional value of wood ash depends on the type of wood that it was made of. According to Sullivan, hardwoods can produce about three times the ash and about five times the nutrients per cord compared to softwoods. He explained that a cord of oak has enough potassium for a garden 60 by 70 feet in area. A cord of Douglas fir ash will have enough potassium for a garden with 30 by 30 feet.

Wood ash also has micronutrients. It has 15% calcium which is a nutrient that is often lacking in most soils and fertilizer mixes. Ashes can improve the structure of soils. However, this should be used carefully since calcium can make soil alkaline with a pH range of 9 to 13.

Wood ash will make soil slightly acidic and low in potassium making it beneficial to most garden plants. However, do not use ash if your soil pH is alkaline or more than 7.0. You must not use wood ash to plants that thrive in acidic soils such as blueberries, rhododendrons, and azaleas. This is also a no-no in areas where potatoes will be planted because the ash can cause scabbing in potatoes.

When using wood ash in lawns that need potassium, you must apply no more than 10 to 15 pounds of ash per 1,000 square feet. This will deliver sufficient amounts of potassium to the soil and to your grass despite rains. You can also add wood ash to compost. You simply mix wood ash to your compost pile and mix it well.

Wear eye protection, gloves, and a mask when handling wood ash. Never throw ashes in the wind. Apply it directly to the moist soil and rake it into the soil. Never use ashes from cardboard, coal, stained wood, painted wood or pressure-treated wood. These materials have potentially harmful substances.

Excess wood ash should be placed in a covered container. Never leave this in lumps or piles because when ash is concentrated in one place, excessive salt can leach into the soil and this could be very harmful to your plants.

Conduct a soil test first!

Before anything else, conduct a soil test. This is very important when using wood ash to your lawn because it can significantly change the pH of your soil. A soil test will help you establish a baseline value.

All soil tests report pH or the measure of your soil’s acidity or alkalinity. The center of the scale is the number 7 which means the pH is neutral. A reading lower than 7 is an acidic reading while higher than 7 means that the material is alkaline or basic. Most plants prefer to grow in slightly acidic soil at 6.5 while some plants require a highly acidic soil at 4 to 5.5 ranges.

The best time to use wood ash on grass is in the fall when you have least ashes. You must save up this year’s ashes for fall use. Don’t plant seeds or seedlings until at least two weeks after ash has been applied. You may also wait until new plants are a few weeks old to apply wood ash.


Wood ash is a good way to improve the nutritional quality of soils especially lawn soil. It contains high amounts of potassium and calcium as well as other essential nutrients for optimum plant growth. There are some important precautions when using wood ash. Be sure to follow these to ensure safety when using wood ash on your lawn or garden.

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