5 Dollar, 1/2 Hour Worm Composting Bin(s)




About: I love to design and make things; and am currently developing a variety of small consumer products.

No flashing lights, bikes, magnets or iPods here. Just worms in a box. Eating.

Update: Due to popular demand for information about how to care for worm bins, I'm thinking about writing a small book about the subject. Please let me know if you'd be interested in having a little worm bin manual! (Yes, I know there is another such book. I'd like to do one in a slightly different style.)

Years ago, when I was poor and under-employed, I craved a worm bin (aka vermicomposter, aka worm composter), famous for the fastest compost in the West. I did research on the web, and found that commercial bins were expensive, as much as US$200 for an Australian multi-tray "worm farm", which was way too big for my apartment-dwelling self anyway.

That winter, I visited my sister in Oregon nursery country, and she had the brilliant idea to use nursery flats as trays. Guess what some of the commercial bins are made from? One U.S.-made bin got started that way, and has since done some customizing, using their own molds. 

I've seen simpler versions of worm bins, a 5 gallon bucket, or a stack big Rubbermaid tubs with a lid. They probably work as well, at least until you want to harvest your worm castings, which you must sift out of the newer bedding and food scraps; not to mention fill a perfectly good tub with a ragged pattern of holes.

The tray version seen here allows you to segregate old from new, in just a few minutes. It also makes trips between "floors" much shorter for the worms. Less crawling, more eating. And pooping. Worm poop is good.

Mine has a couple of issues I have not gotten around to solving, more on that in the last couple of steps.

Update, Sept. '07: After all these years, I finally realized how easy it would be to separate the liquid from the food and castings. The castings I had been getting were thick mud.

Enter the filter! I lined the next to bottom tray with heavy shade cloth, usually used overhead for shading plants, etc. You'll see it in the shade plant section of the nursery where you go to get your flats. I'll post photos later.

Onward to the building part...

Update, : May 28, 2008 See step 7 for some info on how I harvest the castings.

Update March '09: There seems to be a steady stream of questions about how to maintain worm bins. People seem to want more detail than I have provided here, so I'm thinking about writing a small book. 

Update March '12: No book has been written yet, but I'm seriously considering making an ebook/iBook. If you're interested, please let me know, it will help me determine the interest level.

Please let me know, preferably via comment or private message, what delivery method you'd prefer. Paper book?, e-book? I kind of like the image of an intrepid composter outside, muddy hands clutching a Kindle. ;-)

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Step 1: Get Your Stuff Together

I bought 5 nursery flats (the trays that hold a bunch of small, square pots. They are also used to grow ground cover and grasses in. (you buy the whole flat of plants). [people outside the US, please let me know what's used in your country].

A gruff old country nursery man sold me the flats for seventy-five cents each.

You'll need:

- 3-5 (or more if you eat a lot of vegetables) nursery flats

- a piece of heavy 3-5 mil plastic sheeting, big enough to line one tray with a couple of inches coming out over the top edge. This will be the bottom tray. Another piece to lay over the top as a lid is optional. Better yet, a piece of screen to keep pesky flies out.

- shredded or torn paper for bedding. I first used newspaper, then got a big bag of "cross-cut" shredded office paper from the Accounting dept. It works great, and I don't have to tear paper or put it through a home shredder any more.

- Alernate bedding material: Coffee Chaff! It's the outer skin on coffee beans that literally flakes off during the bean roasting process. I've been using it exclusively for over a year now, and it works great. No word from the worms as to whether or not they are getting a buzz, or having trouble sleeping. 

I like this material better because it's a by-product with few "higher" uses; whereas paper can be made into more paper, rather than getting down-cycled into a soil amendment.

- 1 small stick for spreading bedding and food scraps.

- about a pound (a little less will do fine) of red wriggler worms. Start with less if you like, it will just take a little longer to develop a population large enough to fill your trays. Of course, your needs will vary depending on the volume of scraps you generate.

- optional lid to keep varmints and light out. I used a scrap of wood.

- food scraps, vegetable matter only! No fats, which can clog the breathing pores on worm bodies.

Step 2: The Foundation

Choose one tray, line it with the plastic sheet.
I folded the corners as if I was wrapping a gift box inside out. Origami folders will know exactly what to do.
The important thing is that the plastic is folded fairly neatly, so it does not bunch up and prevent the tray above from sitting down straight and comfortable.

Add shredded paper, enough to fill it about 1/4 full. If you're ready to add worms, dampen the paper lightly. Worm literature says, "like a wrung out sponge". Not soggy and dripping, yet damp enought that sensitive wormy skin is not instantly dessicated.

I usually don't put any food in the basement layer, as the worms seem to like this as their living room and bedroom. They tend to go up to higher layers to feed, and congregate in the bottom, where most of the castings (aka worm poop; compost) end up.

Step 3: Second Verse, Same As the First

Only different. No plastic liner this time, set the second tray on top of the first, taking care to make sure it's nested all the way. The natural tendency of the trays is to curve a bit, sometimes it takes a bit of coaxing to get it seated snugly.

It usually works best to put one end in first, then lay down the other. Jiggle and fiddle as necessary.
This is important, as you don't want any leaks, or fugitive worms that may meet an untimely end underfoot, in a bird's beak or squashed at the next feeding time.

This image shows the almost finished product. Note the not so carefully trimmed plastic liner obscuring the foundation tray. On the ends, you can see the ribs that hold the trays up, leaving an inch or so of space between the bottom grids. That's where the food, bedding and worms go.

Step 4: Ready for Worm Move-in

Worms, not just any worms, red wrigglers are recommended. These are a few of mine in the bottom of my bin, just after cleaning out the castings (worm poop), that goes for about US$10 a pound in gardening stores.

They are available to buy, for an equally costly ~$20 a pound. Given my Scottish ancestry and small bank account at the time, I decided to go foraging on my own. There's a horse racing track nearby, and the manager gave me permission to dig around in their old manure piles. I felt a little, er, sheepish, but swallowed my pride and commenced to digging my own pound or so of worms. That was almost ten years ago, and their descendents are happily munching away on my lettuce scraps, banana peels, and mango seeds. Yep, the seeds, which eventually soften up and become cozy little hideaways inside.

Step 5: Care and Feeding

There are more complete care and feeding descriptions elsewhere, I'll be back later to tell what I know.
Meanwhile, if you have a good source for trays, worms or other information, please post it here.

Step 6: The Harvest

Harvesting: Someone asked about harvesting the castings, and I probably did not address that step. Here is a brief description of how I do it. Eventually, I'll post some photos.

I confess to not having read this instructable recently, apologies for any redundancies.

The tray full of castings is usually the bottom one, where most of the worms stay. I usually rotate the trays, put that one on top, and move the entire bin outside.

The worms can't take being in the light, so they head downstairs, encouraged by my gentle stirring once or twice an hour, sometimes once or twice a week. Eventually, they all move lower, though it's a good idea to poke through any clumps. I suppose if you are more patient that I am, they'll all go on their own, with less work for you. I'm a little paranoid about ejecting my trusty friends from their comfy abode, so I am pretty thorough about sifting through the muck to get all the worms I can back into safer territory.

The harvest, and being able to keep the newer and older food separated are for me, the two main advantages to using the tray system rather than having one big tub.

Step 7: Cottage Industry?

I've read about a co-op in India that collects vegetable scraps and makes compost, then sells it as a soil amendment. Given that worm composting is said to be the fastest way to make compost, I wonder if this idea would be useful in rural areas as a "cash crop" that just about anyone can do. What do you think?



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    113 Discussions


    6 years ago on Step 7

    If you haven't already, do the book. I would prefer an e-book because it's faster to get. I'm not all that patient when it comes to getting info !


    8 years ago on Introduction

    Way back when (2006) I posted a question about using non native worms because I was woried about them should they escape into the local landscape 9 (my property borders forest land). Your suggestion to start the bin in direct contact with the ground and "see what critters crawl up into it" was very good. It attracted worms and sow bugs (AKA wood lice- from the forest land) and they started right to work but it took a couple of months to breed to the volume necessary for the compost created by my family of 5. It has been going for three years and is still going strong. Many Thanks.

    1 reply

    Reply 7 years ago on Introduction

    My apologies for the delayed response.

    That's great and gratifying news that you were able to enlist your native worms and bugs in your cause! Sow bugs have found my bin as well, even though it's inside my garden shed. They're good decomposers too, and seem to co-exist happily with the worms.


    1 year ago

    Commenting to save, as save button doesn't seem to be working right now

    Heather Sooder

    2 years ago

    O, please do the book. I have lots of questions. I live in Central Florida and I do not have a shed. But, I do have a shady spot by the house. I compost there without worms. Occasionally, not every year, we get a freeze. We can protect plants from freezing by covering them. I would think the worms would need to be kept moist. Is that true? Can the worms be protected from freezing by allowing them to escape into the ground. Will they come back to my nice cafeteria?


    3 years ago

    do the book let us know.Good Job by the way.


    4 years ago on Step 1

    Please be informed,
    we are goldengreenway company
    big producer of worm composting with high quality and low price.
    we want to have some fruitful co-operation with you ...
    and we offer our product between 1-2$.
    this price just related to worm compost
    with considering the fact that we have various product.
    we can send you the sample when ever that you request of us.
    impatiently we are looking forward to having from you as soon as possible.




    13 years ago on Step 7

    Mulch is pretty cheap these days in most states, so you'd have to scale your worm production up an awful low. In drier areas like Nevada or Arizona it might go for a little more, which puts it in a more reasonable venture. Also, marketing is good: if you advertise it as "100% natural, high nitrogen, red wriggler-produced soil enricher," you might attract the local gardening nut who's afraid or artificial stuff like Miracle-Gro.

    3 replies

    Reply 13 years ago on Step 7

    I should have said for 3rd world use, mainly. That said, I've seen bags of worm castings in garden stores for what I thought were high prices, for a few pounds of material.


    Reply 6 years ago on Step 7

    I live in Tucson, AZ, & last summer I paid $10 for a small bag of worm castings. By small I mean about 8 oz. Good, organic mulch is equally expensive.


    Reply 13 years ago on Step 7

    ...also, worm castings (and compost in general, as far as I know) are generally thought to be fertilizer, to be mixed into the soil, rather than mulch.


    7 years ago on Step 5

    i say do the book and do you recomend this for florida or somthing else


    7 years ago on Introduction

    Please reply to this comment if you'd like to see a small ebook/iBook (and would pay a small sum for it).


    1 reply

    Reply 7 years ago on Introduction

    I would definitely be interested in an ebook/ibook . Preferably for kindle, and maybe around $4? Like the articles and your polite commentary. Keep up the good work!


    Reply 10 years ago on Introduction

    Thanks, though I see no sign of a worm bin there other than a brief mention of it in text. You're not really going to make everyone sift through your un-searchable site are you?? ;-)

    Why not just add an image to a comment on this Instructable?


    Reply 7 years ago on Introduction

    I just checked today, and the account seems to be gone. Rats.
    If anyone else has made their own bin from this 'ible, please post links and photos here!


    8 years ago on Step 7

    Er, you may have missed the idea that this project is about composting rather than raising worms. The intent is to have the worms warm and comfortable, eating to their little heart's content as a way to convert waste into fertilizer. To quote William McDonough, of "Cradle to Cradle" fame, "Waste equals food." Literally, in this case.

    Peat is thought to be endangered these days, and is much more valuable staying where it was created than as a storage medium for worms. As you mentioned, newspapers work well, as does coffee chaff, coir (coconut fiber) and other "waste" products.

    And of course you know that using all caps in digital communication is considered to be yelling.
    IMO, your post is not especially appropriate to this 'ible, and hopefully is not part of the recent epidemic of advertising disguised as comments on blogs, news stories, and, gasp, Instructables!

    Kelly Williams

    10 years ago on Step 5

    Thank you so much for this! I have been wanting a worm bin and couldn't understand why they were all so expensive. This is the perfect solution! I can't wait to get started. Where do you place your worm bin trays, out of the direct sun? Are they sensitive to temps?

    1 reply