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If you love the look of a lush, green lawn, but you don’t want to spread synthetic chemical fertilizers where your kids and pets play, consider feeding your lawn naturally instead. Top dressing a lawn with compost is the best way to provide the long-lasting, slow-release nutrients that encourage optimum turf grass growth. In this article, you’ll learn the many benefits of top dressing lawn, when to do it, and a few different techniques for getting the job done right.
Why bother feeding your lawn at all?
You probably fall into one of three different camps when it comes to lawn care.
- Camp 1: You tend your lawn methodically. You fertilize regularly, mow frequently, and perhaps apply weed killers and pesticides a few times a year.
- Camp 2: You ignore your lawn except for keeping it mowed. You apply no fertilizers, you let the weeds flower for the pollinators, and you only consider pests if they happen to show up.
- Camp 3: You’ve gone no-mow and let your grass grow tall, only trimming it a few times a year. You don’t really even think about your lawn.
I’m not here to pass judgment on any camp. Instead, I’m here to tell you that no matter which camp you fall into, top dressing your lawn with compost is something you should be doing. Yes, it’s a way to reduce the usage of synthetic fertilizers if you’re in Camp 1. But most importantly, for all Camps, top dressing lawn is the best way to improve the overall health of your turf grass and the soil beneath it. It makes your lawn more resistant to pests and better able to choke out weeds. It encourages a deep root system that can better withstand drought and nurtures the beneficial soil microbes that help grasses thrive, whether you mow the lawn every few days, once a week, or twice a season.
Later in this article, I’ll explain each of these benefits in more detail, but for now, let’s talk about what top dressing is and why compost is the best top dressing for a lawn.
What is top dressing a lawn?
Top dressing is the act of spreading a thin layer over the surface of something. In this case, we’re spreading a thin layer of compost over the surface of the lawn, and it doesn’t take much to do the job. You want to add enough compost to introduce a good balance of nutrients and plenty of beneficial microbes, but not so much that you risk smothering your lawn. When top dressing lawn, you only need to spread ¼ to ½ of an inch of compost over the grass. Rain, wind, soil organisms, and human actions quickly move the compost down through the grass and into the soil where it can work its magic.
Why compost is the best top dressing for a lawn
Compost is the perfect tool for the job because:
- It can be finely screened (which means no big chunks of it sitting on your lawn after it’s been spread).
- It’s easy to distribute over the turf (more on this process later).
- It contains a perfect balance of macro- and micro-nutrients that are slowly released over time.
- Quality compost has a pH that’s neutral or close to neutral.
- Compost is absolutely teeming with beneficial microbes that help feed your grass. These microbes digest the organic matter in the compost and release the nutrients in it into the soil. They also help break down thatch (a layer of dead grass stems that builds up at the base of the plants). Oh, and one last – and very important – job microbes perform: they digest the grass clippings that come out of your lawn mower and return them to your soil in the form of growth-fueling nitrogen.
- Compost can be sourced relatively inexpensively by making your own, purchasing it in bags, or buying a truckload from a landscape supply yard. Where I live, many of our local municipalities give away leaf compost that’s made from our local leaf collections for free.
The benefits of top dressing lawn
A top dressing of compost over the lawn pays you back in many ways.
- As the compost works its way down into the soil, it helps aerate compacted soils. This occurs when soil organisms, both big and small, work to digest the compost and they open up microscopic pore spaces within the soil. With regular applications of compost, you’ll eliminate the need to ever aerate your lawn again.
- The microbes present in compost digest thatch, which can sometimes build up to form a thick layer that restricts air and water movement into and out of the soil. A thick layer of thatch can cause rainwater to collect on the soil surface, instead of draining away. When this happens, walking on the lawn feels like walking on a sponge every time it rains.
- A top dressing just ¼ of an inch thick, in combination with allowing your lawn clippings to fall to the ground when mowing, provides almost all of the nutrients your lawn needs to fuel an entire season’s worth of growth. And, if you have clover in your lawn, all the better. Clover leaves are rich in nitrogen, basically eliminating the need for additional synthetic fertilizers when the clippings are left in place.
- The nutrients in compost are released slowly, over a long period of time and with very little nutrient leaching. This means little to no nutrient runoff, which can pollute waterways and ground water.
When to top dress lawn with compost
Top dressing can be performed in the spring, just before the lawn “greens up”, or in the mid to late fall, just before the leaves drop from the trees. Some homeowners opt to top dress their lawns twice a year, once in the spring and again in the fall, with a quarter inch of compost each time. Others opt for just once a year. What matters most is that you spread the compost during a time of year when there’s an increased chance of regular rainfall to help move the compost down toward the roots of your turf grass.
How to top dress a lawn
There are four techniques you can use to top dress a lawn.
1. Top dressing lawn by hand
For this method, you’re spreading the compost by hand. You’ll need a wheelbarrow, a shovel or garden fork (my favorite), and possibly a leaf rake. Use the shovel or garden fork to scoop the compost out of the wheelbarrow, then fling it out across the lawn, doing your best to spread it fairly evenly. You can then spread the compost out more using a leaf rake, if it’s in chunks or if you didn’t fling it very evenly (I mostly skip raking it out, but only because I’m lazy). Frankly, it’s kind of fun to whip shovels full of compost across your yard. Kids love it. It doesn’t have to be perfectly spread or 100% accurate but do try to distribute it as evenly as possible to avoid “extra green” spots where more compost fell or dead spots where too much compost smothered the grass.
2. Use a rolling peat moss spreader to spread the compost
These cool spreaders have a rotating barrel-like structure with metal mesh openings. They are traditionally used to spread peat moss (which is not as good for top dressing a lawn as compost is), but they also work great for distributing compost. Simply fill the rolling barrel with compost and walk up and down your lawn while pulling or pushing the barrel. The compost drops out of the mesh openings and onto your lawn. They cost a couple hundred dollars but are well worth the investment if you have a medium-size lawn. They work best with compost that is dry and screened.
3. Top dressing lawn using a drop spreader
This technique of top dressing lawn uses a traditional drop-style lawn spreader with a big hopper. It works best with compost that is dry and finely screened. Wet or clumpy compost will clog the spreader holes.
Drop spreaders have adjustable holes in the bottom and a mechanism on the handle that lets you set the size of the openings. Set the spreader on the setting with the largest openings and close the lever that shuts the hopper holes. Fill the hopper with compost from a nearby wheelbarrow or truck, go to the edge of your lawn, and open up the drop holes as you walk up and down your lawn in a row pattern. Make sure you cover all of the lawn, refilling the hopper as needed. Lawn drop spreaders with a bigger hopper mean you don’t have to refill as often, but they’re also heavier to push.
It also may be possible to use a broadcast spreader to top dress your lawn. They have a spinning wheel beneath a single hole where the compost drops out. The wheel spins and tosses the compost out onto the lawn, rather than dropping it directly beneath the spreader. However, in my experience, unless the compost is very finely screened and super dry, broadcast spreaders clog more easily than drop spreaders. Still, if you already have one in the garage, feel free to give it a whirl. You might have a very different experience.
3. How to use a tractor attachment spreader for top dressing lawn
If you have a lawn tractor and a large lawn, it may be worthwhile to invest in a tractor attachment to spread compost. These tow-behind units have large hoppers, adjustable hole sizes, and can attach to either a lawn tractor or an ATV. You can also use them to seed the lawn or distribute ice melter on the driveway in winter.
Another option is to invest in a tractor-mounted manure spreader. They tend to be more expensive but won’t clog as readily if your compost is wet or clumpy.
The best reason to top dress lawn with compost
Managing a lawn is one of the most resource-intensive practices homeowners participate in. Hard to believe, but pound for pound, here in North America we use more pesticides and herbicides per acre on our lawns than big agriculture does on food crops. Instead of turning to synthetic fertilizers that cause water-polluting nutrient runoff, harm beneficial soil life, and introduce unnecessary chemicals into your yard’s ecosystem, turn to compost instead. As you now know, the benefits are many and you can feel great about letting your kids and pets roll around in the lawn without worry.
For more about compost and soil care, check out the following articles:
- How to make compost
- Make a DIY compost bin
- Soil pH and why it matters
- The best garden soil amendments