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Does Compost Help Grass Grow? How To Guide

Fertilizers are widely used on lawns throughout the world. But, they can cause more harm than good if not used correctly. Compost, however, is completely natural and also great for the environment. Does compost help grass grow?

Compost can help grass grow when used as a top layer. It provides lawns with a rich amount of nitrogen, potassium, and phosphorus; all of which are essential for grass to survive. However, to achieve the maximum effect on your lawn, it needs to be added at the correct time using the correct method.

To attain the perfect lawn using compost, using the right amount and applying at the right time are essential for lush, green grass. Here you’ll find exactly why it is so beneficial for your lawn, as well as how you can achieve the perfect application.

Can You Use Compost to Grow Grass?

Compost not only helps grass grow stronger and fuller by being a natural fertilizer, but it also strengthens the root system to ensure its survival through winter.

Compost adds a natural layer of microbes which breaks down the dead organic material. It also increases water retention so your grass’ roots can receive all the necessary water they need. And this helps grow your lawn completely naturally, without the need for blue powder.

  • Over time, lawns can develop a very rough top layer known as thatch.
  • Which occurs when there are not enough microbes to break down organic material.
  • This leads to a buildup of organic matter which prevents any nutrients from entering your lawn.
  • Because of this rough top layer, instead of holding onto moisture and allowing water into the root system, it slips right through.

What’s In Compost?

Compost can be comprised of any of the following:

  • Yard debris: twigs, leaves, flowers, weeds, grass clippings
  • Food scraps: eggs, banana peels, apple cores, coffee grounds, tea leaves, nuts
  • Paper goods: napkins, paper towels, uncoated paper bags, uncoated plates, compostable straws, and utensils

Check out our Full List of What To Compost for more info.

All of these items, once decomposed, add an essential amount of nutrients to your lawn, and ultimately lead to a much greener and fuller yard. But, knowing exactly when your lawn will benefit from an added layer of compost is just as essential as knowing what’s in it.

Here’s a helpful video about topdressing a lawn with compost, with more info below:

When to Put Compost on Lawn

The US and Canada have 13 Hardiness Zones. Knowing which zone you live in is essential when it comes to knowing what perennials (including grass) can survive in your yard year after year.

Knowing your zone will also give you a rough indication of when your lawn should start to see some growth each year. Once you have that, you will have a good indication of when you want to add your first layer of compost.

Compost is best dressed when your lawn is just beginning its active growing season. This is early enough in the season to give the microbes enough time to break down the organic material; but not too early that the compost suffocates the lawn. In most cases, you will want to add your compost in Late Spring and Early Summer. 

If added too early in the year, compost can prevent sun and water from entering an already dormant lawn. This could damage parts of the lawn that have not had a chance to begin growing yet. If added too late in the season, compost will not achieve its maximum effects on your lawn, leaving the roots less strong for the winter.

Some people like to use topsoil as an extra layer of nutrients to their lawn instead of using compost. This method can present its challenges. Let’s take a look below at using topsoil vs compost for grass.

Topsoil vs Compost for Grass

Topsoil is pretty much what it sounds like. It is the top layer of soil that comprises the highest density of nutrients available in a landscape. For these reasons, it can be extremely beneficial for starting a lawn.

Instead of compost, many people choose to use topsoil to achieve their perfect lawn. It is especially popular in large landscape projects, such as re-leveling, but it can be more damaging than good.

In most cases, it is the first 12 inches removed for development projects. However, there is no way to filter out just the good when it comes to taking an entire top layer of soil off a property.

  • Along with the nutrients, much of the topsoil contains cement leftover from a previous foundation.
  • It can also be filled with clay, slit, and harmful waste.
  • For these reasons, topsoil can be a bit of a gamble when it comes to increasing the density of your lawn and is preferred only when you are starting a lawn from the very beginning.

Compost is much lighter and less intrusive on a partially developed lawn. It is also comprised of 100% organic material so you always know exactly what you are applying. The exact amount, however, is crucial.

How Much Compost to Add to Lawn

The great thing about using 100% organic material on lawns is you really can’t burn the roots through over-fertilization. You will still want to be mindful about how much you add on top of the already existing grass. There is no need to use more than is necessary.

Here is a breakdown of how much compost you might need if purchasing a 1.5 cubic ft bag:

Lawn Size sq ft1000200030004000
Number of Bags7131925

In most cases, you will want to evenly spread ½ to ¼ inch of compost over your entire lawn. This would also be a great time to add new seed to your compost mix, as you are already taking time to spread it over your lawn.

It is recommended to aerate your lawn prior to fertilizing. This not only allows for more oxygen and water to enter the grass, but it helps the compost push through the top layer.

I recommend a Broadcast Spreader Like This One (link to Amazon)

The easiest way to cover a large amount of area evenly is to use a spreader. Once applied, rake in the compost to ensure it enters each hole created from aeration, and you are all set!


Adding anything to a lawn can seem daunting; there is not a lot of room for error when it comes to grass. But hopefully, you feel much more assured that using 100% organic material with compost on your lawn, will only bring beneficial growth for years to come.

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