10 May Soil Management
Have you ever heard of the saying that you are what you eat? The same can be said for your lawn, and your lawn’s health starts at the source of nutrient uptake, i.e. the grass’s roots and the soil it inhabits. Soil provides nutrients, water, air, and a place of anchorage for your grass roots. Soil can also contain insects, diseases, nematodes, or overall poor nutrient quality. For this reason, it is important to have a general understanding of soils and how they interact with plant roots. For example, your soil’s pH reading helps determine just how interactive your soil and roots are. The two basic concepts this blog will cover are the variety of soil types, and a basic understanding of a soil’s pH.
There are three types of soil: sandy soil, clay soil, and loamy soil.
Sandy soil is coarse and gritty to the feel and water moves through it quickly, so it has a low water holding capacity. For this reason, sand is poor in nutrient content.
Sandy soil’s nutrient content can be improved by regularly adding organic material, such as compost or well-rotted manure. This will help improve (slow down) drainage, increase the water holding capacity, and as a result increase plant nutrients.
Clay soil is reddish brown and is fine and powdery when dry. In contrast to sand, water moves through it slowly, so it has high water holding capacity—typically, too much. Clay soils can be rich in plant nutrients, but the pH is often too high or low, so those nutrients are not available to plants.
Clay soil can be improved by adding organic material, such as compost or well-rotted manure. This will improve (increase) drainage and provide more appropriate water holding capacity. Organic material will also lighten heavy soil.
Loamy soil is dark brown and contains clay and sandy soil in moderate proportions with some organic material. Water moves through it at a moderate rate, so it has a moderate water holding capacity. It is rich in plant nutrients. For this reason, loamy soil is ideal for growing healthy grass.
pH is a way to explain the amount of hydrogen ions in a solution. In other words, the more hydrogen ions in a solution, the more acidic the soil. Think of pH as the mouth to your grass by which it consumes plant nutrients. The pH scale ranges from 0, highly acidic, to 14, highly alkaline. The mouth of your grass is “wide open” when it has a pH of 6.0 – 7.0, which is neutral and ideal for growing healthy grass. This means that your soil is in the ideal range to receive nutrients.
Grass grown in soils that are too acidic or too alkaline cannot consume any plant nutrients, whether they occur naturally in the soil or are applied in the form of fertilizer. If you are applying fertilizer to your lawn without knowing the pH to your soil, you could very well be wasting your money. Don’t do it. Instead, invest more time and money in determining the pH balance of your soil first. pH soil testing kits are inexpensive and reliable. Here are some recommended products below:
To improve soils that are acidic (below 6) you will need to add lime (calcium carbonate) to move the pH to neutral. To raise soil pH by one point in a typical sandy loam soil, spread crushed limestone in the fall at a rate of about 50 pounds per 1,000 square feet unless your liming product recommends a different spreading rate.
To improve soils that are alkaline (above 8) you will need to add granular elemental sulfur to move the pH to neutral. To reduce soil pH by one point, say from 8.0 to 7.0, spread elemental sulfur with your garden spreader at the rate of 20 pounds per 1,000 square feet, unless your sulfur product recommends a different spreading rate.
To learn more about the nutrients that go into your soil, check out Are Micronutrients Missing From Your Lawn Care Program?
For more information on how to efficiently get these nutrients with our recommended fertilizer suggestions, read our Get Your Lawn Drinking Its Nutrients blog post.