Top dressing is a great way to repair damaged lawn areas, smooth out uneven spots, and amend poor soil.
What Is Lawn Top Dressing
Top dressing is the process of spreading a thin layer of material (usually compost, screened loam, or sand) over your lawn, or sections of your lawn. This layer is only about a 1/4″ and is meant to be thin enough so that existing grass can grow through the freshly applied material.
Top dressing is done for a variety of reasons which include improving soil conditions and drainage, leveling and smoothing out uneven spots, and creating a layer for seed to germinate.
Best Material for Top Dressing Lawn
Choosing the right material for top dressing will depend on what you are trying to achieve:
*Compost- Compost is a great top dressing material if you’re looking to overseed and repair damaged or thin areas of your lawn. It’s also a great choice for improving soil drainage and adding nutrients to your soil, especially if you have clay soil. It’s even more effective in improving soil conditions if done right after Core Aerating. This allows the compost to work its way deeper into the soil. A lot of lawns that look hopeless can be turned around just by core aerating, top dressing with compost, and then overseeding.
*Sand- Sand is the ideal choice if you’re trying to get a very level lawn. Maybe you have some mild bumpy spots you’re looking to smooth out, or a mole pushed some tunnels up and made the surface bumpy. Whatever the situation, sand is a great way to get things smooth again. Choose a pretty fine to medium textured sand.
Sand is actually the material of choice used to level golf greens. Just note, sand is used more for a fine tune leveling. If your lawn is very bumpy and has larger divots throughout, sand is not the ideal choice. For those areas you’re better off adding screened loam. As a general rule, if you’re going to violate the 1/4” thickness rule to level a bumpy lawn then use screened loam instead of sand.
*Screened Loam– Screened Loam is a versatile top dressing material that has some of the combined benefits of compost and sand. Different garden centers and bulk material distributors have different types of screened loam, so do some research before buying. Screened loam is usually an even mixture of Sand, Silt, and Clay, but getting a screened loam that has compost mixed with it is the ideal choice. Screened loam can used for amending soil, seeding, and leveling.
Benefits of Top Dressing
1. Improves Soil Health- Top dressing is a great way to add nutrients to your lawn organically. Using compost or quality screened loam with organics will build up beneficial microbes in your soil. It’s also a great way to correct water retention problems and drainage. In sandy soils, adding compost will increase water retention. In clay soil compost will lighten the soil and improve drainage.
2. Breaks Down Thatch- Beneficial microbes in compost and screened loam with organic material helps to break down the thatch layer in your lawn.
3. Levels Lawn- If you have areas of your lawn that are bumpy, top dressing is a great way to smooth out these areas. For light leveling use sand. If material needs to be spread over a 1/4” thick to level an area, use screened loam.
4. Helps Seed Germinate- Seed to soil contact is important for seed germination. If overseeding your lawn, top dress with compost or screened loam to create a nice bed for the seed to germinate.
5. Fix Lawn Without Starting Over- If your lawn has damaged sections, or overall your looking to renovate your lawn and make big improvements, top dressing allows you to do so without ripping up your existing lawn.
Top dressing is even more effective when done after core aerating.
When Is the Best Time to Top Dress
For cool season lawns late summer/early fall is best. Avoid top dressing your lawn in spring if possible. Spring is when weed pressure is strongest and you’re more likely to get weeds after top dressing. Instead, for cool season lawns block weeds in the spring with a pre emergent and in late summer/early fall pull the trigger on your top dressing project.
For warm season lawns the best time to top dress is early summer. This is when warm season grasses begin to take off and fill in bare spots.
How to Top Dress a Lawn
If you’re looking to make huge improvements in your lawn without ripping the whole thing up and starting over then follow the step by step process below. Even if your lawn is covered in weeds, you’d be shocked at how top dressing and overseeding can turn things around.
1. Determine What Material to Use
Determine what top dressing material you should use. Compost and Screened Loam with Organics are ideal choices if you’re seeding or trying to improve soil conditions. Sand is the ideal choice if you’re just trying to smooth out small bumpy areas.
2. Kill Lawn Weeds
In the weeks leading up to top dressing your lawn, it’s a good idea to kill lawn weeds using a lawn safe, liquid herbicide. If you’re seeding after top dressing use an herbicide that contains Mesotrione. Mesotrione is safe to use right before, and even at the time of seeding. Other herbicides can negatively effect seed germination rates so Mesotrione is definitely the best herbicide to use when you plan on seeding.
3. Dig Out Bad Sections
If you have specific areas of poa, bentgrass, or other patches of nuisance grasses then it is best to manually dig these out. These grasses can be tough to control with herbicides.
4. Spread Material
There are a few different options for spreading the material over your lawn. The most professional way, is to use a machine such as this Ecolawn Applicator. You could check your local rental place to see if they have a machine like this for rent. Of course you could also hire a local company to spread it for you if that is a local service companies provide.
It’s more likely however you’ll be doing this the manual way. Some people like to fill a wheelbarrow up with their material and then use a shovel to get the material out of the wheelbarrow. Once on the shovel they just fling the shovel and spread the material over the lawn. This is fine if just top dressing a small area.
But for larger projects you’re probably better off making a bunch of tiny piles throughout your lawn as shown below. Keeping the piles small will make it a lot easier to rake out later on and ensure that you are creating a thin layer.
5. Rake In Piles
A leveling rake is the best and most professional tool for the job. Second best would be this aluminum landscape rake pictured below, but other garden rakes will work fine. Just take your time to rake out clumps and work the material into the lawn. Remember, you want a very thin layer so any grass that is being covered will be able to works its way up through the layer.
6. Apply Starter Fertilizer
Apply a slow release fertilizer such as Milorganite 6-4-0. A slow release fertilizer is ideal because it’ll slowly provide nutrients as seeds germinate.
7. Apply Seed
After applying your starter fertilizer it’s time to apply your seed. Once again, use a broadcast spreader and follow the seed application rates on the seed label. Don’t over apply seed!
Do some research before just purchasing any bag of seed. With seed, you get what you pay for. Stay away from contractor mixes
GCI Seed is a great place to buy seed online. Scotts also has some great grass seed options that you can usually find in the big box stores.
Don’t forget to setup irrigation! If you don’t have an irrigation system then check out this battery operated irrigation controller. You can schedule them to come on multiple times a day.
You can set up to 4 zones per controller and get at least 2 sprinklers per zone. This will cover a lot of square footage and get you out of moving sprinklers all day.
The early to late summer weather can be unpredictable. Really hot days can pop up. Be sure to monitor the weather and plan for these hot days. New seed needs to be constantly damp to germinate.
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