Summary: The best lawn soil is loam soil, a soil that drains well and contains – clay, sand, and humus – in the right proportions
Question: We want to improve our lawn soil. It is a very clay soil lawn, so what is the best soil for grass? What can we add as a soil conditioner for a new lawn? Nathan, Columbia, SC
Answer: Nathan, soil poorly or well drained boils down to the space in the soil, the size of the pore spaces, and the little spaces and cavities between the separate soil particles.
These spaces in the soil all depend on the elements which make up the soil media and in what ratios they are all put together.
From a working perspective, the overall makeup of soil comes from 3 different ingredients:
- Clay
- Sand
- Humus
Mud, we’ve all seen it, worn it, or got it on our cars – that is clay. Most people know what sand is; somewhere along the line, people have seen a beach in person or through pictures. However, not everyone knows what humus is.
Humus is the end result of organic matter that has decayed, or dead animals and dead plant material.
When living things die, they, over time, become soil as micro-organisms feed on, break down and convert the animal or plant into what we call humus.
This substance gives the layers of soil on the surface black or dark brown.
For a healthy lawn, the soil must drain well, be rich in nutrients, breathe, and grow a vibrant root system. For the lawn soil to drain well, it needs – sand, clay, and humus – all in the right ratios.
Test the soil first using testing kits to determine the nutrients present in the soil (nitrogen, phosphorus, potassium, and others). It also helps identify the soil type and the soil ph level.
If the soil testing finds out that you’ve got acidic soil, you may want to apply lime to make it less acidic. Otherwise, you may need to select acid-loving plants to grow on your turf.
Since you describe your soil as very clay, the pores spaces are very tight, do not drain well, and hold too much water.
For those with more sandy soils, the lawn area’s soil has large pore spaces and does not hold enough water.
When sand, clay, and humus all come together in the right amounts, the humus acts as a “glue” to bind all the materials to create soil with large and small pores that hold moisture and air.
Lawn Soil Like Post-it Notes
This is the type of soil that can very loosely be described as loam. It is strange; people know it almost by instinct when they come in contact with this type of “perfect soil.”
It is sort of like “post-it notes.” They stick to some things but not like tape. A good loamy soil cannot make a mud pie when wet but does not fall apart when it is dry.
All the soil particles, sand, clay, and humus, hold together in small clusters made up of smaller granular structures.
The best type of soil for a lawn is surface soil.
A soil that allows the root system of new grass seed or a new lawn to grow and stretch its roots, breathe and hold a rich reservoir of nutrients to create a lush carpet of lawn grass soil, inviting the kids to play and calling for the lawn mower to give it a trim.
You can change the soil texture by adding organic matter, such as peat moss, compost, quality topsoil, and rotted manure, while working it into the soil several inches deep in late spring.
Remember, adding soil amendments is important if your topsoil has too much clay before planting grass seed.
Cool-season grasses, such as Kentucky bluegrass, tall fescue, fine fescue, bentgrass, and perennial ryegrass, thrive in areas with cooler climates and colder winters.
Common warm-season lawn grasses, such as Bermudagrass, flourish where summers are hot and winter is mild.
It”s important to plant warm-season grasses, also known as southern grasses, including St. Augustine grass, Bermuda grass, centipede grass, and zoysia grass, as they thrive in areas with hotter summers and milder winters.
