Sheet Composting – Coffee Sacks for the Final Layer ~ Part 6

The Interbay Mulch method was developed by a coordinator at the Interbay P-Patch, “The Garden Between the Bays” in Seattle, Washington. The Interbay P-Patch is one of Seattle’s largest community gardens and is recognized as a shining example of resourcefulness and sustainability. The soil enriching method has been compared to sheet composting (or lasagna gardening). While there are definitely similarities in these methods and some common benefits, the Interbay method differs in one way – burlap is used to cover the entire layered bed.
~~The Shoestring Gardener eBook

Part 6

Well, I believe I’ve shared a lot of good information with you about my sheet composting adventure. As I’ve mentioned before, when spring rolled around the final result was a very nice, very humus-rich soil. I do truly believe my tomatoes, herbs and flowers that I planted in this garden bed grew much better than previous years.

But … I utilized something that you rarely will see on top of a layered, cooking compost pile — burlap coffee sacks. Why coffee sacks? Well, I’ll tell you.

I’d never heard of the Interbay Mulch method. While doing research for my Shoestring Gardener eBook, I came across information about it, and through some deep digging online, found the how-tos of layering up a compost bed in this way and found other documentation attesting to why coffee sacks make a premiere “final layer” versus what most composting folks use — black plastic.

Here’s the link to the Seattle P-Patch gardening “how to” article: Interbay Mulch Guide. This is very interesting information and a document worthy of saving for future reference.

Why Burlap or Coffee Sacks?

A scientific-minded P-Patch coordinator did some very in-depth research on the results to a sheet layered compost pile using burlap, or coffee sacks, as the final layer and cover. Turns out that burlap is far superior over black plastic because:

  • Optimum dark, moist conditions are maintained for faster decomposition by soil organisms. Also, dried out burlap can absorb a lot of rain before any excess water passes into the layers, allowing a more evenly distributed level of moisture for the pile. In addition it is not so tightly woven that it stops the all-important required level of oxygen that is essential for decomposition.
  • The burlap material is an excellent environment for promoting rapid and abundant growth of a multitude of very beneficial fungi and other organisms in the compost.
  • The worm population will explode! They love the dark moist environment. Plus, the burlap will keep birds from being able to eat them. More worms for your new garden bed. 🙂
  • Also, two layers of burlap on the pile are better than one.

While gardeners in Seattle have no problem finding an almost limitless source of burlap — Seattle is known as the USA’s coffee capital and coffee beans come in burlap bags — the rest of us will probably have to buy the burlap. But, after seeing the price of what really thin burlap-by-the-yard cost at the local Wal-Mart, I was determined to do some further investigation and try to find coffee sacks, and to see if it’d be cheaper to use them.

In places like Seattle where there are lots of coffee roasting companies, I’ve read that in many cases they are happy to give away the burlap coffee sacks. So, that’s a great frugal (cheap!) way to get them. But, most of us don’t live in an area where there are many roasting facilities, which was my case.

The few I did find either: a) said they didn’t have any to give me; or b) would sell them to me, but only had a couple to spare. This wouldn’t work, as I figured I’d need about 20 coffee sacks (which was exactly what I ended up using) based on a sack’s standard size and the size of my garden bed. Plus, I was going to use two layers of sacks, as recommended in the Interbay Mulch method.

I finally found a very “cheap” source, a coffee roasting facility in the Pacific Northwest, where I could buy 20 sacks — the sacks were free, but had to be purchased in lots of 10, with shipping at $10.00 per ten sacks. But, what a deal! A buck apiece! If you need to find coffee sacks because there are none available in your local area, you’ll find them sold on eBay and other online sources. Just search for “used burlap coffee sacks for sale” or other variations of this. I’m sure you’ll find a source within your price range.

In the next post of this series, I’ll share more information about using the coffee sacks and what to do with them in the spring. So … stay tuned for Part 7. 😉

If you want to learn more about composting, and lots of other eco-friendly gardening methods and great DIY projects utilizing recycled materials, please head over to The Shoestring Gardener information page. Thanks!


  1. This has been a GREAT series. Practical. And now I know where to find a b bag connection. Thanks!

  2. I find it so hard to read your article and to find parts 6 and 7 but no link for parts 5,4,3,2,1 I feel I need to read those as well. It’s like starting at the end of a movie. Please advise!

  3. Karen:

    Perhaps you’re not familiar with using “Search” boxes on websites? Or the category listings over in the right-hand sidebar??

    A very easy way to reference all of the articles in this sheet composting series is to type in these words “sheet composting” into the search box and voila. You will get the results for all the articles. OK? Thanks for asking.

  4. Interesting articles about sheet composting – I’m getting ideas for how I can utilize this technique in my garden.
    I agree with the other posters – Well done!

  5. Hello, just wanted to say, I loved this post.
    It was practical. Keep on posting!

  6. Hurrah! Love the info on this sheet composting you’ve got here on your blog. I’m going to give this method a try. thanks for sharing with the rest of us.

  7. Way cool! Some extremely valid points! I appreciate you writing this write-up
    and also the rest of the website is very good.

  8. Melody KirkWagner says:

    Boy, the days of cheap burlap sure seem to be over. I’m in the PNW – would you mind telling me which roaster was selling them? I’m looking for one now. Thanks!

  9. Claudia Brownlie says:

    Hi Melody:

    Gee, I can’t remember now which roaster I bought them from as it was many years ago. I do remember though that I did find the roaster via a rather extensive online search. I’ve just tried doing a search to see if perhaps their name would come up to jog my memory, but no luck. They may also have stopped selling the used bags. Anyway I know that even buying used coffee bean bags can be expensive, but you may luck out by persevering in your search and calling roasters in your general area. Check out eBay, also, though I remember used coffee bean bags weren’t very cheap there, either. And you never know … maybe you might even get a couple for free from a few different roaster just by calling ones in your area. Also try this keyword search query as it may help you find a source: “used burlap coffee bags for sale direct from roasters”

    Good luck and I hope you have some success in finding an affordable source! 🙂

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