If your lawn doesn’t have very good soil or is just bumpy, uneven, or rough, there’s a way to improve it without digging the whole thing up and starting over. The answer is “top-dressing,” which is a way to gradually make corrections by adding a thin layer of amendments to the surface.
Golf courses regularly top-dress greens with sand in an effort to keep the surface as smooth and even as possible. Home lawns benefit from top-dressing for a host of other reasons, especially when they’re top-dressed with compost or compost blends.
Besides smoothing out bumpiness, these top-dressings add organic matter and nutrition to the soil, introduce thatch-decomposing and disease-preventing microbes to the lawn, and over time, improve the root-stunting, compacted conditions that are often common if you have clay soil.
How to top-dress
The trick to top-dressing is adding only enough new material to aid the soil without smothering the existing grass. A quarter-inch layer is enough that grass crowns can slightly elongate to adapt to the slightly higher soil surface.
The material you use depends on your goal and the soil type. On golf greens, sand makes sense because the turf is fertilized regularly, irrigated often, and smoothness is very important. In a home lawn where maintenance is less intense and standards not as perfectionistic, the top-dressing material can be the same as or similar to the existing soil – assuming it’s reasonably good.
If the soil is shale, clay, or otherwise poor, improve it by top-dressing with fine or sifted compost or a blend of 40 percent compost, 40 percent peat moss, and 20 percent sand. Your own homemade compost is one of the best (and low-cost) options. If you don’t have the time to make your own - bagged, store-bought compost is also a great option for small jobs. Otherwise, many of the same businesses who sell bulk mulch also sell bulk compost or even bulk blends mixed specifically for top-dressing or garden soil-improving jobs.
Top-dressing materials can be scattered by hand over small areas. Or use the “dump-and-rake” method by dumping small piles throughout the lawn and using a rake to evenly spread the material to a quarter-inch layer.
Extra top-dressing pointers
- If you have a big lawn, you don’t have to top-dress it all at once. Do the front one year and the back another year. Or tackle the job in sections.
- Early fall is an ideal time to top-dress cool-season lawns, especially when done right after core-aerating and/or over-seeding. Spring is an ideal time to top-dress warm-season grasses, and it’s the second-best time to top-dress cool-season lawns.
- Top-dressing can be done each year to gradually improve underlying soil. However, once you choose a material, use the same one each year so you don’t end up with different layers of different textures, which can impede drainage.
- Don’t top-dress over thick thatch layers. While organic top-dressings can prevent thatch buildup, remove thatch that’s more than a half-inch thick before top-dressing so you don’t just bury it and encourage further buildup.
- On sandy soil, top-dress with a coarse, sand-rich top-dressing. Top-dressing coarse, sandy soil with compost or similar fine materials will fill the pore space and harm drainage.
- If you’re planning to overseed at the same time you top-dress the lawn, spread the seed after you spread your top-dressing material. This is so you don’t bury your seed too deep. Once the seed is spread, use a rake to gently work the seed into the top-dressing material.
- It is okay to apply fertilizer after top-dressing. While top-dressing will provide long-lasting benefits to your lawn, fertilizer may provide immediately available nutrients, especially if you have just overseeded as well. Use a starter fertilizer, such as GreenView Starter Fertilizer, to give your grass seed the best start.