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I have a compost pile that has a lot of "browns" in it, dead leaves and wood shavings mostly. Can anyone recommend sources for large quantities of "greens"? I've been putting in my kitchen scraps but it doesn't seem like much compared to what I already have...

I've also started stealing the used coffee grounds from my work but I've heard this can make my compost too acidic. Any suggestions?

3 Answers 3

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After a bit of googling, it looks like coffee grounds are close to neutral pH, so I wouldn't worry about acidity there.

If you have too much "browns" and not enough "greens", you could take a different approach: instead of adding your dead leaves to the compost pile, make a dedicated leaf mold pile. This will take a long time (up to two years) to break down, but when it does it makes a nice low-fertility soil amendment. No need to worry about acidity here either: leaves are acidic, but the end product from your leaf mold pile will have nearly neutral pH.

As an aside, do you have a constant stream of wood shavings that you're adding to your compost pile? If so, have you considered other ways that you might use these around your yard, e.g. as mulch? I only ask for the same reason I suggest the leaf mold pile -- using the shavings in some other way could help you balance your compost pile better.

Now, on to the answer to the question you posed... sources of greens (high nitrogen):

  • kitchen scraps
  • coffee grounds
  • lawn clippings
  • fresh weeds
  • seaweed
  • animal manure
  • apple pomace
  • human hair
  • hops (brewery waste)
  • a number of other sources of vegetable waste

As for places to acquire these ingredients:

  • As you mention, you can get coffee grounds from work or from a coffee shop.
  • You could try making arrangements with the cafeteria at work or a local restaurant to use their kitchen scraps. (But I'd guess that they'd want a commitment from you to haul everything away, which could be more than you can use. Depending on how careful they are, you may get some contamination with stuff you can't or don't want to compost, e.g. meat, dairy, trash.)
  • You can ask for veg waste from the produce department at your local supermarket.
  • Ask your neighbors if you can take their lawn clippings from their untreated lawns. You don't want to import herbicides into your compost!
  • If there are any kind of fruit/vegetable processing plants locally, they may have waste products that you could get for free.
  • Ask for a bag or two of hair from your local barbershop. (According to "The Rodale Book of Composting" on p93, 6 pounds of hair has as much nitrogen as 100 pounds of manure.) Make sure to mix well with your leaves/shavings because hair mats down easily.
  • If you have a local brewery, ask if they'll let you take away a few buckets of their waste. Hops or grain mash are both good additions to the compost pile. If they're soggy, make sure you layer well with your dry leaves and shavings.
  • If there are any farms in your area, or people with backyard horses or chickens, you may be able to get manure free for the hauling.
    • Beware that horse stall bedding that includes wood products (shavings or sawdust) will behave more like a brown (or neutral) than a green.
    • Beware that manure from horses will contain a lot of weed seeds.
    • Beware that hay as a bedding material will contain a lot of weed seeds.
    • Beware that manure from commercial feedlot operations may contain high levels of salts.
    • Even with all of these caveats, I'm a big fan of manure in the compost pile, mainly because for me it's home grown, easy, and free.
  • You can grow a "compost crop":
    • Comfrey is a perennial with leaves that can be harvested multiple times a year and added to your compost pile.
    • Various annual/biennial cover crops make a nice addition to the compost pile: buckwheat, clover, small grains like oats (if you cut them while they're green -- before they become mature, toughen, and turn into straw which is high carbon).
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    I hadn't really thought about it, but it makes sense that hair has a lot of nitrogen (it is all protein) - but doesn't it take a long time to breakdown?
    – winwaed
    Jan 27, 2012 at 13:34
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    @winwaed: I cut my own hair and add it to the compost, it breaks down quickly. From the Rodale reference above: "Like feathers, hair will decompose rapidly in a compost pile but only if well moistened and thoroughly mixed with an aerating material. Hair tends to pack down and shed water, so chopping or turning the pile regularly will hasten decay." Sources I see in searches also mention pet hair, e.g. from groomers. The shavings (and leaves, if they are shredded) that Abe has would be a good aerating material.
    – bstpierre
    Jan 27, 2012 at 14:01
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    Fair enough! I do put pet hair in our compost, but it is such a small volume, you wouldn't notice if it took years to breakdown.
    – winwaed
    Jan 27, 2012 at 14:04
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    I would also say that I do see search results mentioning problems with composting hair -- definitely experiment with small amounts to begin with so you can figure out how to make it work. If I was using larger amounts than what comes off my own head (which is producing diminishing amounts of compost fodder as the years go by...), and didn't have large quantities of other materials, I'd probably try thin layers of mixed hair+leaves - soil or compost - mixed hair+shavings - soil or compost.
    – bstpierre
    Jan 27, 2012 at 14:06
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Another source of nitrogen I read about is the urea in urine ( how the human body gets rid of excess nitrogen ). Take a leak on the pile every now and then and it will add some nitrogen and water.

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    I know there are a couple farms in the UK who have somewhat amusing signs saying "pee on this pile!" for exactly this reason. It's funny but very true, urine is a great additive to compost. BEWARE - Human feces is NOT safe for compost, lest you might think you could save on the sewer bill completely! Jan 31, 2012 at 16:24
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Starbucks has their "garden grounds" program where they give away free, used coffee grounds. If they don't have any packages made up they'll usually just hand you a big, white bag of grounds if you ask. I put about 100 lbs of starbucks in my leaf pile each fall and come away with wonderful brown compost the next year. I also think I have the most hyper worms in the neighborhood. :-)

As for hair from pets (dogs and cats) and humans... don't compost it if you have problems with rabbits and other pests in the garden. Just scatter it around the plants that are vulnerable and the herbivores then believe that their safety lies in different areas.

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