Reduce Future Water Requirements
Adding topsoil for grass and grading your area will be the final steps in preparing for sod installation. If you have already added your topsoil in the previous step (Soil Testing, Measure Your Space, Controlling Weeds), you can proceed to final soil grading now.
Healthy sod establishment is best ensured when installed on well-prepared, moist, nutrient soil with good porosity. Coupled with soil cultivation, adding new soil ensures your sod’s roots will have adequate nutrients, drainage, and oxygen. Cultivating the land & adding topsoil can increase water retention in the soil and reduce your new lawn’s water needs by 20-40%.
How Deep Should Topsoil Be?
Most soil issues cannot be fixed by adding a thin layer of organic material to the surface of compacted and clay soils. Topsoil is typically thought of as the top 6 inches of soil. We recommend adding at least 2 to 3+ inches of topsoil and rototilling it 2 to 3+ inches into the existing dirt to get the recommended 6 inches depth. Adding a depthless layer of topsoil without mixing it into the earth can lead to shallow root development, compaction & drainage issues, or shock the grass once the roots penetrate the existing soil layer.This soil calculator will estimate how much soil you need to achieve the correct topsoil depth.
Choose Appropriate Soil Type
The soil blend you should use will depend on the existing dirt in your yard. For optimal results, you should consider performing a soil test before choosing & purchasing your topsoil so that you can select the correct soil. If you have heavy clay soil, it is best to choose a mix with more organic material, rototilling it into your existing clay soil. Do not attempt to amend your clay soil with sand, as this can make the ground harder & more compacted. You can read more about amending clay soil here.
Amending Clay Soil
Clay soil is plentiful throughout many parts of Texas. Although clay is an essential part of healthy soil, it can cause issues if overly abundant. Probably the biggest concern with clay soils is root establishment. Once the grass has established its root system, it will typically perform very well in clay soils; however, compaction issues should be addressed seasonally.
Although there are ways to correct clay soil compaction issues after installing your grass, it is best to amend your clay soil before planting your new grass. Do not use sand to blend into clay soil as an amendment. Although you will likely encounter some articles instructing to use sand to amend your clay soil, it can be counterproductive, making the clay concrete-like. If you must use sand, be sure to use the largest coarse sand particle size available for this method to be effective. Finer sand particles can fill the tiny holes in clay structures producing a rock-like install area.
Sand-based soils have sand volumes of at least 50% of the volume of clay. You would need an enormous amount of sand to produce sandy loam soil for your lawn. Unless you are an expert, it would be best not to attempt this method.
This video does a great job at explaining how different products work to amend clay and compacted soils. Below are some products that work great to amend clay soil pre-planting.
- MicroLife/MicroGro products, such as Brown Patch, Humates Plus, and Bioinoculant
- Natural Guard HuMic Granular Humic Acid
- [N-ext] Bio-Stimulant Pack
- Espoma SPF30 30 Lb Soil Perfector
- Turface
Final Soil Grading
Next, you will do the final soil grading. Begin by building up areas along your home/structures and filling any low lying areas with new soil. Use a landscaping rake to move the soil around the site, making sure to disperse it so that for every 100 feet, the yard is sloping 1 foot. You can check this by using a 2′ x 4′ and level, as illustrated in the instructional video below.
Asses the Grade & Look for Low Spots
Step back and view the yard from the street or sidewalk, looking for any recessions. Additionally, make sure there is no sloping toward the structures on your property. Low areas that will keep grass submerged during irrigation or rainfall can stress the grass and prevent strong roots. Gradual slopes that lead away from your property and out to the street are recommended for ideal water flow. In some cases, you may need to install a drainage system to divert excess water from a problem area to an area that could use water.
Tips & Warnings
- Have some extra topsoil on hand in case you need to build up any areas, fill in any low spots, or add more soil base to blocks of sod that lost some soil during harvest, transport, and handling.
- Use a hand leveler & 2’ x 4’ to gauge the slope grade.
- Instructional Video
- Do not apply fertilizer to the soil or new grass for at least a few weeks
What You’ll Need
- Topsoil
- Rototiller
- Landscaping Rake
- Level
- 2′ x 4′
- Hoe
- Shovel
- Landscaping/Protective Gloves *Optional*
- Other PPE *Optional*
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