Regardless of the best of efforts to maintain a beautiful lawn year-round, sometimes lawns will still show signs of weakness. Weeds, fungus, grubs, and heat stress can plague your lawn. Top dressing may be just what is needed to bring your grass back to its former beauty.
What Is Top Dressing for Lawns?
Top dressing a lawn is the process of spreading a thin layer of material, usually compost or sand, over your lawn. The top dressing layer should be about ¼ inch thick and is intended to amend the lawn’s soil while allowing existing grass to grow through.
When it comes to top dressing, more does NOT equal better.
If the top dressing layer is too thick, it can suffocate the existing grass.
What are the Benefits of Top Dressing Your Lawn?
- Improves Soil Structure
Top dressing adds nutrients to your lawn and improves drainage.
- Improves Water Retention
- Breaks Down Thatch
Microbes present in top dressing materials help break down thatch, a brown layer of mainly dead grass that accumulates in some lawns between the green grass blades and the soil surface. A thick thatch layer restricts air and water movement in and out of the soil.
- Levels Lawn
If there are bumps and divots in the yard, top dressing is a great way to help flatten out these trouble spots caused by settling, worms, the freeze-thaw cycle, and water runoff.
- Improves Stressed Lawns
Top dressing helps fill in bare spots and control weeds.
When is the Best Time to Top Dress a Lawn?
The best time to top dress a lawn is when it is actively growing. Do not top dress a lawn when it is extremely hot, dry, or dormant.
For cool season grasses such as fescue and bluegrass, late summer or early fall is the best time to top dress. For warm season grass such as Bermuda, zoysia, and centipede late spring or early summer is best. For a good rule of thumb, allow three to four mows after top dressing is completed before severe heat or cold sets in.
Items Needed to Top Dress a Lawn
- High Quality Compost or Top Dressing Material
- Wheelbarrow – to transport material to top dress the lawn
- Broadcast spreader (optional – needed if overseeding and/or adding fertilizer)
- Grass seed (if over seeding)
- Fertilizer (optional)
How to Top Dress a Lawn?
Step 1: Test Your Soil
If you are considering top dressing your lawn, you’ve probably already noticed issues with your grass. This is an important time to test the soil and make amendments if necessary. Your local extension office can assist with soil testing to identify your soil composition and recommend amendments.
Step 2: Kill Existing Weeds
A few days before top dressing, spot treat any weeds in the lawn using a post emergent herbicide that eliminates weeds without killing the grass.
Step 3: Mow Short
Mow the grass to the short end of your grass’ recommended height range, being sure not to cut more than a third of the grass blade to avoid stressing the lawn.
Step 4: Aerate
If one of the goals of top dressing is improving the soil, it is best to aerate prior to top dressing. Opening up the thatch layer through aeration creates space for the top dressing material to penetrate the surface of the soil.
Step 5: Spread Grass Seed (Optional - If Overseeding)
Overseeding may be beneficial if there are thin or bare spots in your lawn, and aeration holes provide a perfect environment for overseeding.
Step 6: Fertilize (Optional)
While fertilization is optional, you can fertilize before topdressing a lawn. Apply fertilizer after aeration, but before top dressing material is put down. Apply a starter fertilizer, which has a higher phosphorus (the middle number) to promote root growth and early development.
Step 7: Choose Quality Top Dressing Materials
Be sure to purchase quality materials to add nutrients to your lawn. Selecting what top dressing material to use is one of the most important steps to top dressing your lawn. The top dressing material you choose should be similar in texture and composition to the existing soil.
The most common choices are compost, topsoil, sand, or a custom blend of materials. High quality finished compost or a custom blend of compost, topsoil, and sand is the most often recommended top dressing material.
However, the best choice for your specific lawn will depend on your current soil and any issues within your lawn. Coarse sand will help increase drainage and allow more air to access the root system, while topsoil will add organic material to your existing soil. Sand also aids in maintaining a level yard over time as it does not compact easily.
Top dressing materials can be purchased from home improvement stores, garden centers, local nurseries, or even landscape companies.
Step 8: Make Small Piles
Use a wheelbarrow to transport and distribute top dressing material around the yard in small piles. The top dressing material you use should be dry to allow for easy spreading. Making many small piles will ensure you are create a thin layer and make it easier to rake out later.
Step 9: Gently Rake Piles
Break up any clumps and be sure to gently rake out each pile so it is not more than ¼ inch thick. Half the height of the grass blade should be visible once the material is raked out. Overly vigorous raking could damage your grass.
Step 10: Irrigate
Water your lawn after topdressing to help settle the material and keep it in place.
*Note: Do not mow directly after top dressing a lawn.
Best practices include leaving the lawn undisturbed for 7 to 10 days before mowing.
How Often Should I Top Dress the Lawn?
While routine top dressing does improve thatch and soil nutrient composition, it is best to treat bare spots as needed and top dress the entire lawn every few years.
Top dressing is a lot of hard work, but if done properly, you’ll see positive results leading to a beautiful, lush lawn.
Have more questions about caring for your lawn? The Certified Turfgrass Professionals at NG Turf are happy to answer any lawn care questions you may have. Give us a call at 770-832-8608 or email info@NGTurf.com.