Wood ash is good for your yard when used as part of an overall lawn care plan with soil testing, composting, fertilizing, aerating and monitoring. Wood ash raises soil pH and contains essential nutrients good for soil and necessary for healthy plants and lawns. Considered a low-grade fertilizer by most lawn care professionals, wood ash contains potassium, phosphorus, magnesium, aluminum and sodium along with other micronutrients, including calcium. 

Test Your Soil

Testing to determine baseline soil chemistry is a good way to start before wood ash or other fertilizers are applied. Basic soil tests are widely available and easy to use, or call in the professionals for a more comprehensive analysis. Applying wood ash alone runs the risk of making your soil too alkaline, so a baseline soil test before you start is a good idea. Wood ash contains little or no nitrogen, and so applying wood ash to lawns is often done in concert with other fertilizer applications.

Add Wood Ash to Compost

Applying wood ash to lawns and gardens in the fall is an excellent way to raise soil pH and alter soil alkalinity, in the same way that lime or limestone lawn applications do. But adding wood ash alone to lawns can be tricky, producing lye and salts when wet, so consider adding your ash to compost first. Then spread the ash-compost in the usual way with an even distribution. Water lightly after application as this prevents losses and maximizes the benefits to your lawn. Don't combine wood ash with standard nitrogen-rich fertilizers or spread wood ash at the same time you are fertilizing. A mixture of wood ash and nitrogen fertilizers can produce ammonia gas.

Wood Ash Lawn Benefits

Healthy lawns prefer slightly acidic soils, but if pH is too low, poor plant growth and even mortality results. Wood ash lowers soil acidity and raises alkalinity or soil pH. Getting the right balance promotes year-round lush, green and luxurious lawn growth. Wood ash improves soil structure and strengthens plant cells. Typically, good results from wood ash applications on lawns are visible within a few weeks to a month after treatment. 

You can test your wood ash to get a better handle on how it will affect your lawn and garden. Different kinds of wood produce different levels of nutrients when burned to ash; for example, hardwoods like maple and oak have higher nutrient concentrations than softwoods, such as pine, spruce and fir. 

What Is Lawn Aeration?

Aerating your lawn removes plugs of soil to create openings that allow oxygen, nutrients and water to penetrate the soil and enable healthy grass growth. It also allows for the release of carbon dioxide that's within the soil. Aerating a lawn requires manual or mechanical tools. 

Why Aerate Your Lawn?

Over time, your lawn’s soil becomes compacted and tight. Soil compaction comes from everyday activities such as walking, playing sports, driving and parking vehicles on the surface. Poorly drained areas of a lawn tend to suffer the most from compaction. Dry hard soil, bare patches and poor drainage are signs that a lawn is compacted. This soil lacks the porosity that allows air, nutrients and water to enter the ground, allowing turf roots to get the nourishment necessary for a green and lush lawn. Excessive thatch between green grass and soil can lead to turf damage. Thatch consists of dead and living matter, including leaves, roots and stems. Thatch can hamper grass growth, but aerating loosens and opens the underlying soil, allowing lawn roots to grow deeper.

When Should You Aerate Your Lawn?

Lawn care experts recommend aerating your lawn during early fall for hot weather grasses, including Bermuda grass and St. Augustine grass, and in the spring for cool weather grasses such as bluegrass, fescue and ryegrass. Avoid lawn aeration during drought and extremely hot weather. During hot weather, the openings created by aeration tools lets the heat penetrate the soil, and it may damage roots. The day before aerating, water the lawn or wait for a soaking rain that provides at least 1 inch of water. The water softens the soil and helps the aerator extract the soil cores.

Which Aerator Is Best?

Examples of manual aeration tools include spikes attached to shoes, handheld core aerators and garden forks. However, spikes and garden forks don't result in the desired effect because they leave the soil plugs in the ground. Lawn and garden experts warn that using forks or tines for aeration can contribute to soil compaction. Lawn professionals recommend using core aerators that remove soil plugs and redistribute them on the lawn.

A core aerator or one that pulls plugs of soil from the ground is the best tool for aerating your lawn. While you can use a manual core aerator, if your yard is large, a mechanical aerator can be most effective and help you finish the job in less time. A tow-behind aerator hitches to a tractor or lawn mower and allows you to cover a lot of ground quickly. Gas-powered walk-behind and stand-on aerators are also efficient. An electric walk-behind aerator eliminates the need for gas.

After aerating your lawn, leave the soil plugs to decompose naturally. Set up a regular watering schedule, fertilize the lawn with a high-nitrogen product and overseed with new grass.