NEWBIES: the difference between compost and mulch

ken_adrian Adrian MI cold Z5January 16, 2010

these two are often confused ....

to simplify it to the max ...

COMPOST a SOIL AMENDMENT/ADDITIVE.. which.. over time.. will improve your soil ...

MULCH is a SOIL COVERING which aids in water retention and weed suppression ... which will become two of your biggest challenges.. once your plants quit dying.. lol ..

you can use compost as a mulch.. but you should NOT use mulch as a compost....

the biggest problem is that compost is not a weed suppressor .... weed seeds need soil contact and sun to germinate.. if you cover the soil ... you can retard germination ...

BTW .. if you ever need to go digging in your bed.. you pull back the mulch ... do your soil work.. and then replace the mulch ...

on the other hand .... mulch is often a wood product... when wood IS INCORPORATED into soil [like an amendment might be] .. it leaches nitrogen and other things... and absorbs water ... in the process of rotting .... this would complicate your life.. not aid it ... wood left on top of the soil ... as in mulch ... WILL NOT DRAW nutrients from the soil .... so you would NEVER use mulch as a compost/amendment ...

these two topics are graduate level course in many Ag colleges.. i am trying to simplify it to the extreme.. simply to get a point across ... so correct me if i am way off base... but lets work in simple terms for the NEWBIE ...


i have a bunch of tree guys who dump wood chips ... most is used for MULCH ... once it sits long enough for the greenery to burn out ...

piles that i dont move in 3 years are/become compost ... i have too many of those around to admit.. lol ...

if you want to speed decompostion of a pile of wood to black gold... add 49-0-0 and copious amounts of water ... and then wait about three years ...


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Lilyfinch z7 mid tn

Ken, can you tell me, if i wanted to help my clay soil , should i get compost or garden soil delivered? I have a composter but its a slow process. I would like to add it to get more worm action going. Thanks!

    Bookmark   January 16, 2010 at 11:48AM
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ken_adrian Adrian MI cold Z5

hey lily.. started a new post .. just for you.. and your clay peeps ... you are welcome ...


    Bookmark   January 16, 2010 at 11:56AM
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Boy, Ken, can you ever oversimplify!!

Probably the best statement made in the above is: "you can use compost as a mulch". In fact, I would recommend it highly. It has the best array of nutrients of any organic mulch and has virtually no nutrient tie-up issues, which many wood-based mulches do. And it very handily accomplishes all the other things a mulch is supposed to do: if applied at an appropriate thickness, it DOES suppress weeds, it insulates the soil, it slows evaporation of and maintains soil moisture and aesthetically, it is much more pleasing in a perennial planting bed than chunky wood chip or bark mulches (and I won't even address rock mulches!!). If you have access to it, either your own or a bulk product, I'd recommend compost over any other organic mulches, especially for perennials.

Lilyfinch, if you intend on tilling the additives into the soil, go with the compost. If you are berming or just establishing raised beds or planting areas, the topsoil (or better yet, a garden planting mix) will be fine.

    Bookmark   January 16, 2010 at 6:35PM
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I have used my own compost made from seaweed, used coffee grounds, banana peels and shredded leaves for the last 8 years. The soil we have is not that great, but having used compost as mulch the gardens now have soil which is dark and rich. It is also the only 'amendment' I use. :O)

    Bookmark   January 16, 2010 at 9:03PM
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donnabaskets(Zone 8a, Central MS)

I have used compost for mulch too. It was very effective.

In addition to what ken said, I'd add that compost can be used in a number of ways.

When building a new bed, it makes a great soil amendment. In this case, you mix it (as much as you can get your hands on) into the native soil with a tiller or a spade.

In existing beds, it makes a wonderful "top dressing". You sprinkle or spread 1/2 to 1 inch of compost right over the soil surface (over old mulch too, if you like) of the bed to within an inch or so of the plant crowns. This is like a vitamin tonic to your soil. Expect fabulous results!

It is the best thing you can add to planting holes of new plants. Just dig a couple of scoops of compost into the soil as you set out plants. They'll like it!

Mulches don't have to be wood products. Pinestraw and chopped leaves are great mulches. This is why so many of us mulch in the fall: that's when free mulch is all over the place. If you use leaves, pick them up with your bagged lawnmower. The mower will chop them as you pick them up. One caution: don't use leaves from an extremely weedy area. They'll be full of weed seeds. If you use them, compost them before spreading them onto your beds. (Guess how I know this? ....:)

I am often asked if I take my old mulch up each year before adding new. NO. Over the course of the year the mulch begins to compost into the soil. This process speeds up considerably if that mulch gets stirred around alot by the gardener. Everywhere it touches the soil it begins to break down. So, each fall, I lay several inches of fresh mulch right over the top of the old mulch, which has now become or is well on the way to becoming compost. Simple! :)

    Bookmark   January 17, 2010 at 8:37PM
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ken_adrian Adrian MI cold Z5

newbies need to start with over-simplification of concepts.. and when the muse hits.. they have a base from which to learn ...

overly complicated descriptions only befuddle and confuse newbies ....

compost can be a mulch or incorporated .. but mulch is not a compost that can be incorporated ...


    Bookmark   February 1, 2011 at 9:44AM
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