Compost or Mulch

I was talking to a person about planting this year’s garden and told them to compost the garden, then mulch heavy. He looked at me like I had 3 heads and asked, “isn’t compost and mulching the same thing?” It hit me that the 2 processes may not be understood by all. So, let’s talk about mulch (mulching) and compost (composting).

Compost is nutrient rich and full of life that improves the soil and feeds roots.  For people that till, this is what they till in the ground, but generally, they don’t lay it on the surface of the soil.  

Compost is what growers like to make by following compost rules to assure that the right bacteria grow and break down organic matter. When done right, the compost will conduct heat that will kill bad bacteria and most weed seeds.

If you have a small homestead learn how to make small batches of compost here:

Now, mulch is used to keep consistent moisture and keep weeds (plants you don’t want growing in an area) down. It insulates the soil, makes for low maintenance walkways, and keeps precious topsoil from run off. Mulches can be plastic (synthetics), stone, wood chips, rocks, straw, grass clippings and even paper.

This part can be a little tricky if you are new to gardening. You cannot use mulches in place of compost, especially if you are tilling. What I mean is that you would not till in stone, wood chips, rocks and such. Even if you don’t till, adding these common mulches overtime will not act like compost, not typically. These mulch options should be used only as mulch.

Compost can be used as mulch. Compost can be put on top of the earth and is usually done by no-till gardeners and permculturists. It’s best to make positive that the compost was well made to kill as many of the weed seeds or you will most likely have a garden full of plants you didn’t intend on.

Why would you want to use compost as mulch? Compost, again, will be nutrient rich, and as rain and snow happens, it will leach into your soil and introduce that goodness, naturally, into the earth. It will bring worms and other positive bacteria.

If you are worried about weed seed, make or bring in composted wood chips from tree trimming services. They won’t have any weed seeds and can smother out what you don’t want growing. So, I hope you can tell what should and shouldn’t be used for compost and much.

Common Mulches

Wood mulch
Wood mulches are commonly found in bags or you can get them by the scoop. They are usually used for landscaping, but they are of low value.

Grass clippings
Grass clippings can and should be used as a mulch. They will smother weeds, but as they break down, they add nitrogen to the soil.

Straw is basically a grass. The benefit is that the seed heads are harvested for a grain crop which makes them good cover that won’t seed.

Stones can be pebbles, brick, or other concrete pathways. Stone should have a landscape cloth barrier, or you will have a nightmare of plants growing through your rock.

Plastic, landscape cloth
This is about the most secure way to easily hold moisture and prevent plants you don’t want growing. I find that I don’t feel right about using plastic mulches because they don’t let the earth breathe, so I prefer landscape cloth.

Plastic mulch (courtesy of Wikimedia)
Plastic mulch (courtesy of Wikimedia)

For more on mulching take a look at:


Grass clippings
Spread out the grass clippings for a few days while turning them a few times a day so they may dry out.  If you add fresh cut grass to a compost pile, it will turn it anaerobic which leads to a smelly pile.  This improves Nitrogen content by 10%.

Food wastes
Food waste should not be tossed in the trash bin. Most food wastes can and should be composted. Foods like popcorn, spices, fish, brew waste, molasses, potato peels, carrot peels, old bread, coffee grounds, tea bags, old pasta, milk, citrus waste, weeds (before they make seed heads) and even paper products that are not shiny can be composted. People say not to put meat because animals may attack your pile, but you can add them to your pile as long as it is hot enough to kill pathogens.

Not all leaves compost well! Some leaves, like oak leaves, can take years to break down. I’m not saying not to use them, but you should chop them up first or use them as a natural mulch.  Pine needles should only be used for acid-loving plants like berries or not more than 10% of compost for all plants. Leaves make an amazing compost because they have minerals that normal compost won’t have. Trees have very deep roots that bring those old minerals up via the leaves that they drop in the fall. Don’t bypass this amazing source or nutrients.

Leaves (courtesy of Wikimedia)
Leaves (courtesy of Wikimedia)

manures make great compost, but not all manure is equal. Some manures like rabbit and goat manure can be used fresh. Other manures from cattle and poultry should be hot composted for a year to make usable. They are high in nitrogen and pathogens. Composting for a year kills the pathogens and makes it usable for your garden.

Vermicomposting uses worms, usually red wigglers, to eat the food and turn it into worm poop. This is a very valuable additive to soil and is safe to use fresh.

Worms from Coffee Compost Pile (courtesy of Wikimedia)
Worms from Coffee Compost Pile (courtesy of Wikimedia)

Mushroom compost
Mushroom soil is organic matter used to grow mushrooms in. Mushrooms are perfect for breaking down organic matter and turning it into great earth.

Wood compost
The thing about wood is that while it breaks down, it robs the soil of its nitrogen, so, if you don’t use it right, or you till it into your soil, you have some serious problems. If you compost the wood chips, till them until they fully break down, and you will have a fantastic additive for your soil. Like the tree leaves, your wood chips are full of goodness that was buried deep down in the earth and brought back up for use.

You may not have thought about the difference between mulches and compost, but there is a clear difference. Both are important and should be used properly in order to get the best results out of your garden!


  1. Mollison taught to use mulch and described it as composting in place as the mulch will eventually break down into compost. He taught no need to use labor to “make” compost when you can get nature to do it for you over time right in place at the plant(s).

    1. I completely agree with you. In the woods nobody is making compost by turning. In the woods it is just a matter of layering not mixing. I do the same. From time to time i layer with leaves, small branches and greens. Thats all the ground in my climate(humid tropics) needs. In the humid tropics nothing doesn’t take long before breaking down except from woodchips and sawdust. Layering woodchips, sawdust, greens and animal poo on the ground makes a nice groundcover and a perfect compost for plants without too many work. You have to let nature do the work because nature is and knows the best.

      1. I agree with both of you. I wrote the article to inform on methods. I much in place myself chop and drop. A big part of my mulch/composting is wood chips and comfrey. Comfrey is amazing and fast growing. I grow it periodically through my property just for chop and drop.

        Thanks for reading!

  2. This common theory of mulching etc leaves out a very important real world aspect for those that dont live in high rainfall areas. Some mulches prevent rain getting to the roots underneath. Straw for example can absorb all of a shower of rain leaving the roots underneath dry. Also some mulches and composts become water repellent when allowed to get bone dry. So if you don’t make a bowl shape in it the water just runs off it. Potting mixes and composted wood chips can do this. In low rainfall areas you need a more open mulch that rain can flow go straight through.

    1. Good point anything that is really dry will repel small amounts of water. This is why permaculture is so amazing. Planting trees and shrubs in these areas can turn deserts into an oasis.

      It’s a fine line where mulches that allow water in will also allow water out faster. I don’t have desert experience so I don’t know where that line is.

    2. Reverse it up (hugelkulture) pop your compost on top of the mulch and even till the mulch in with the compost on top. The mulch is a sponge that can keep your water where you want it at the roots or where you don’t on the surface😎

  3. It seems that we make it more complicated than it is. Look at what Nature does. Generally, she keeps the soil covered with dead plant material, whether it be in the forest or in the field.

    Always use mulch and disturb the soil minimally so that the fauna can turn the mulch into soil organic matter. The only time that I can see adding compost is in a situation where food production is extremely intensive and the soil fertility depletion rate might be greater than the replacement rate.

    1. Yes, complication is never a good thing in nature. I have a small plot and I am in a situation where I grow intensively. I have to bring in local wood chips, get leaves from my neighbors and manures from my Amish neighbors. Along with this I use many green manures I grow.

      It’s really amazing that when you grow intensively those mulches constantly need to be replaced. We have to remember that the forests aren’t hit with food production like most homesteads are.

      Thanks for reading and your insight!

  4. You state in this article,” If you add fresh cut grass to a compost pile, it will turn it anaerobic which leads to a smelly pile. “. This is so wrong I wonder if you have ever made compost at all. Fresh grass is the best thing you can add to a compost pile to heat it up. It can become anaerobic if you add too much water to your compost pile. I make a 30′ x 4′ compost piles of leaves and fresh cut grass every year and spread 3” of the compost every year to my gardens.

    1. Indeed, fresh cut grass is amazing for heating up a pile. High nitrogen without the drawbacks of manure (disease organisms, salinity.) I love the stuff. I think that if people don’t spread and turn it properly in the pile, it clumps up and can get anaerobic.

  5. Hi.
    Thanks for the great article.
    I live in a dry warm climate with has less than 300 mm annual rainfall.
    For my fruit garden I am thinking about “Back to eden gardening” which is the same thing….
    Do you think this will work for me ?
    Our soil is loom type soil and becomes dry within 5 -6 days after a good irrigation…

    Will this help me if I cover the soil with about 10 inches of organic matter consisted of grass clippings, leaves and etc to retain moisture?


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