IrisPrincess
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What's the Difference Compost & Mulch?

What's the difference??? And how do I do either to a plant in the ground? These questions might sound stupid, but I honestly have NO CLUE about mulch and compost. THe only thing I know about composting is how to make it :) Thanks so much for any help!!

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Troppofoodgardener
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To me, the main difference is this..

Compost is the stuff that goes UNDER plant roots. You put it in the soil, so it helps the plant grow.

Mulch is the stuff that goes ABOVE plant roots. Helps to retain moisture in soil, keeps weeds out.

But everything rots down eventually.. and this is where mulch can become compost, in a way. It just won't have as much nutrients as well-rotted compost.

Good on you for being able to make compost, it's hard to get the balance right sometimes. 8)
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AkeenGardener
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Yep. I think the 2 are related. Compost is the rotted down by product of your garden and kitchen waste (nothing cooked) that you use to dig into your soil and mulch to me is the stuff that you put on the top of the soil to feed and help retain moisture (and to earth up potatoes). You could use well rotted compost as a mulch :)

I wouldnt worry too much. If you can make compost,which isnt always easy, you are well on your way.

Dead Rabbit
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why do you say compost is superior to mulch,,,even after the mulch has rotted down to compost?

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rainbowgardener
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Mulch is usually one substance... we lay down leaves or wood chips or straw or something over the soil. It does eventually break down into humus.

But compost is made up of many ingredients, kitchen scraps, fall leaves, weeds, yard wastes, maybe some manure. So the compost contains a much greater range of nutrients from all the different ingredients in it.

For example if you use leaves or wood chips for mulch, they are high in carbon but low in nitrogen, can actually draw some nitrogen from your soil in the process of breaking down (but more so if you till them in, than if they are just sitting on the soil). The kitchen scraps, manures and other things you add to compost are high in nitrogen so the finished product is much more balanced.

So for the original poster: "compost" is the finished product that comes from your compost pile, from the aerobic breakdown of a whole bunch of different ingredients, specifically including greens (nitrogenous) and browns (carbonaceous) (see the greens/ browns sticky at the top of this forum). It can be used on top of the soil as top dressing or in the soil as in putting compost in your planting holes.

Mulch is a layer of organic materials, usually all one kind, that we lay down on top of the soil to suppress weeds, hold water in, etc. They are both important in the garden, but they are different.
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toxcrusadr
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One more way of looking at it: compost is material you've encouraged to break down as far as it can to produce a soil amendment. Mulch you don't necessarilly want to break down - you want it on top of the soil to do its thing. Of course mulch does break down eventually.

I use free shredded yard waste as mulch, and it has enough leaves and grass in it that it does break down pretty fast, leaving the shredded wood that takes a bit longer. That's OK because our soil was pretty bad when we started. We just keep piling it on and let the worms do the rest. Especially in perennial beds or around shrubs and trees where we can't dig to amend the soil.

When I was a kid we dumped the grass clippings on what we called 'the mulch pile' out back. Many years before I learned the difference between compost and mulch. I think a lot of people are the same way.
Tox

DoubleDogFarm
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Paper, cardboard and even plastic are catergorised as mulch.


Eric

rot
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horses and mammals

..
Compost can be used as mulch but not all mulch is compost. I like grass clippings for mulch and I really like coffee grounds with grass clippings on top of that for mulch.

to sense
..

toxcrusadr
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Rot, you read my mind, I was just posting in the coffee grounds thread about using grounds underneath with something on top.

To elaborate on my comment above about 'decomposing mulch', another thing I do sometimes is put compost around plants (like tomatoes) during the growing season, as a side dressing/fertilizer/mulch. Cover that with grass clippings or other mulch that will hold the moisture in, and you have a layered mulch that is also feeding the plants. One reason this works great is that the worms will come up into the compost layer and begin eating/tilling it in.

Basically when I layer like that, I put the most decomposed stuff on the bottom to feed the soil and worms. The closer to being soil it is, the closer to the soil I place it. And the more mulchy stuff on top.
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rot
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Not a mind reader

..
Tox,

I had the worms doing the tilling concept and the grass clippings was just something I had been doing on hard bare earth and getting good results so I was able to apply that to crusty layers of coffee grounds once it finally occurred to me.

If I had read your mind I might have had a more complete concept where the more decomposed stuff goes on the bottom and is covered by the less decomposed stuff. I've covered compost mulch with grass clippings before too but I hadn't put together the more general application as you had. Since I'm a lousy mind reader, it's a good thing I read your post.

to sense
..

milifestyle
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Compost has bacteria, worms, insects and other organisms that turn the compost into plant available nutrient. Mulch on the other hand is usually fresh and provides no nutrient value in that state. Typical mulches would include Wood chips, Pine bark, Shredded branches etc. Some people refer to pebbles, scoria, sand, gravel and other ground coverings as mulch but these obviously have no nutrient value.

The Helpful Gardener
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Mulch is just a soil covering. I often use compost as mulch...

Confused yet?

HG
Scott Reil

rot
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Of course I'm confused

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Mulch is soil cover that protects from the sun and the elements while allowing water through. So plastic bits might work for mulch but, a contiguous sheet of plastic film blocking water from the soil wouldn't.

So you you mulch with grass clippings or wood chips or even compost that would eventually break down (feeding the soil in the process) and have to replace that or you could buy chewed up tires spray painted green or brown that never break down but do end up getting submerged in the soil as they collect dust and leaves and so on.

As plants take from the soil, you need to keep feeding it anyways. So why not cover with something that feeds the soil while protecting the soil from the sun and keeping the moisture in the soil?

to sense
..

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Troppofoodgardener
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I wonder what Irisprincess has to say about all this discussion, seeing as they started the thread... :wink:

Has any of what anyone said helped?

It seems the moral of the story is everything will rot and can become compost eventually. Compost can even be used as mulch and vice versa.

Although I'm not too sure about using recycled rubber (ie. chewed up tires spray painted green or brown) as mulch for food growing. I've heard that it's ok for ornamental & non-edible plants, but probably not best for veggies/herbs/fruit.

See the trouble you have caused Irisprincess?!? :lol:
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The Helpful Gardener
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Rubber as mulch is fine if you like arsenic, cadmium, and PAHs.

Otherwise, no...

:evil:

HG
Scott Reil

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I guess I *do* live under a very large rock. I've never heard of rubber "mulch." Thanks be to all deities, spirits, and the Most High.

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rainbowgardener
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[url=https://www.gardeners.com/Wide-Recycled-Rubber-Edge-Border-Mulch/EdgingMulches_Mulches,37-492,default,cp.html]recycled rubber mulch[/url]

they (and lots of other garden catalogs) sell it in all different shapes, rounds to go around the base of trees, etc, and usually at least a couple different colors.
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The Helpful Gardener
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Shredded and crumbed tires increase the surface area and therefor the leaching of the listed toxins (among many others).

Disturbingly some organizations trying to legalize this as a "bulking agent" to compost... :roll:

Fer cryin out loud...

HG
Scott Reil

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applestar
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I see them most often used as playground mulch.... :shock:

The Helpful Gardener
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Yeah, nice... :roll:

[url=https://www.allbusiness.com/government/government-bodies-offices/13887364-1.html]Here's something to think on[/url]. EPA is testing now, but the results aren't in. Still, with the list of known chemicals in vulcanized rubber, to use this in an exposed high surface area manner like crumb, with no solid safety data to date, is clearly irresponsible.

HG
Scott Reil

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Maybe we should start using Asbestos fiber around playground equipment. :roll: I bet it's nice and soft. :shock:

Just kidding folks. Rubber mulch is a dumb idea.


Eric

milifestyle
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I agree with Scott, Rubber "Mulch" is a joke... just a cheap way of getting rid of tyres and "appearing" to be Environmentally friendly. I doubt any productive life or bacteria would survive long under it...

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