Introduction: Worm Bin Bag for Indoor Vermicomposting and Easy Separation of Worms From Compost

Worm composting is an easy way to turn your food waste and shredded paper into rich fertilizer for your plants. You can also feel great about keeping your food waste out of the landfill, where it turns into methane, a stinky greenhouse gas. Worm composting, on the other hand, does not stink - don't believe me? Try it yourself!

As a long-time "worm composter" or vermicomposter, I have tried many different types of worm bin systems. I've made several of those simple boxes with holes drilled in them, wood ones, rubbermaid bins, etc. and while the worms seem happy in there, I am too lazy to separate the worms from the compost that results. I've also tried those stacking type, both the homemade type and the expensive worm farm type. I like those better, but I'm still not happy with lifting out those dirty, heavy trays to get to the good stuff in the bottom tray. It always gets my clothes and basement dirty. I read about a funnel shaped, plasticized bag called the "Worm Swag", which uses a "flow-through" system of composting where your leftover food goes in at the top, the worms hang out up there, eating the food and the finished compost can be harvested from the bottom. This inspired me to make my own worm bag integrated into a table I called the Digestive Table, which can be seenhere. People emailed me, wishing this was easier for them to build themselves, so I came up with this simplified version. I call it the worm bag.

This version of the worm bag is made of wood, so you'll need some tools, a saw, a drill, a carpenter's square and a palm sander. If you don't have access to these, or you just don't feel like getting dirty, you might be interested in the laundry hamper worm bag, which only requires sewing a bag and purchasing a laundry hamper frame (around $20). Mine is a nice sturdy chrome style from the Container Store, pictured below. The bag part of this Instructable is designed for the wood frame style, so you'll need to adjust your measurements if you go with the laundry hamper frame instead. I decided to focus this Instructable on the wood frame style, because it is a little cheaper to build and more customizable.

I spent around $40 on materials. This is what you will need and the approximate cost:

$7.50 for 1.5 yards of fabric - 100% polyester felt. Ecospun from Joanne Fabrics is what I've used here because I like that it is made of post-consumer recycled bottles. I've also used landscaping fabric.
$1.79 for a package of 2 cord stops Joanne Fabrics
$2.59 for a spool of thread - 100% polyester or nylon. Cotton will disintegrate, so don't use it for this project.
$4.24 for 1 length of pine, 8' x 2" x 1"
$6.48 for 2 lengths of pine, 6' x 2" x 1
$5.00 for a Rubbermaid wash tub - or another brand that has a 12.5" x 12.5" sized tub
$5.00 ? for a 1/4" thick piece of plywood that is 20" x 15" - not really sure how much this is, since I had some around.
$3.00 ? for 16 wood screws 1 1/4" long - again I'm guessing on price here
$3.00 for some wood glue
$3.00 ? for 2.5 yards of nylon cord - I actually just used some old hiking boot laces I had around.

The finished project measures 24" tall x 20" wide and 15" deep. It will fit nicely in your home, pantry, basement or even at your office. Impress your work friends with your recycling gadget that eats coffee grounds, teabags, unwanted lunch scraps and shredded paper, turning it all into office plant fertilizer!

Step 1: Layout Your Fabric

We are starting with the fabric bag sewing part, then moving onto the wood construction.

The polyester felt fabric comes 72" wide and you'll need to get 1 1/2 half yards of it. The EcoSpun fabric I chose at Joanne Fabrics was only $5 a yard and I saw a lot of great colors there. I picked a dark color because I did not want the coffee grounds and other foods to show stains. I'm not sure if they would though.

This fabric is not as thick as it needs to be to strong enough to hold all the worm goodness and keep it dark enough inside for them, so it is doubled up. In the pattern youll see the basic layout and where to fold the fabric over. After folding your fabric, you will have a rectangle that is 42" x 36". Get a piece of chalk so you can map out where to cut it.

Step 2: Chalk Mark the Measurements on the Fabric

Now that your fabric is folded over, we will layout the pattern seen in the previous picture. Start by marking 35" over from the longest edge (the one that is 42"). Then mark 3" down, along the other edge (the one that is 36" because the fabric is folded over). Mark 24" down that same edge. Then place the ruler or tape measure as seen in this picture to mark over 12.5" and 24.5".

Step 3: More Chalk Marking...

Those last 2 marks you made at 12.5" and 24.5" over are the bottom part of the bag. These marks should also be marked at 1.5" up, going towards the folded edge. Then make diagonal chalk mark lines to connect the top marking to the bottom marking as seen in the picture. I used the tape measure as a straight edge in the picture here.

Step 4: Finally Cutting That Half of the Bag and Laying Out the Identical Next Half.

Layout the second half of the bag along the edge opposite of the folded edge. This can be done exactly the same way as the last layout with chalk like I did here. If you are smarter, you'll instead cut out the first one so you can use it as a pattern to cut out the second half.

Step 5: Pinning the Top and Bottom Edges for Sewing

Okay, so I don't have an overall picture with pins in it, but the notes show you where they should go, along the top and bottom edges, except for the folded edge, which is already connected.

The detail image shows how the pins go in along one edge.

Step 6: Sew Each of the Pinned Edges (3)

Sew along each of the edges you just put pins into. I made a seam around 1/2' to 3/4" from each edge. No need for perfectionism here.

Step 7: Fold Each Half Inside Out and Insert Nylon Cord in Top and Bottom Edges

Each sewn half is like a tube now, that should be turned inside out so the seams are on the inside. They can be stacked on top of each other now and the nylon cords (or shoelaces) can be strung through the top and bottom of the bag. The cord needs to go through each half, right next to the sewn parts and loop through, connecting both halves. See the detail image. If you are using my old shoelace method will need to tie 2 together to span the length of the top edges.

Do the same for the bottom edge and slide the cord stops onto the ends to hold them together. Do it on the top cords too.

Step 8: Pin the Sides of Bag

Put pins in the sides to prepare for sewing. There are four layers of polyester felt here - a thick chunk that needs to be held into place for the machine to tackle.

Step 9: Sew the Sides of the Bag and Turn Rightside Out - Last Step for the Bag!

These need to be double stitched for strength. I first made 1/4" seams on both sides, then came back and sewed another row of stitches at 1/2". Don't sew all the way to the top and bottom edge though, you have to be careful to end each side right before hitting the nylon cord. If you stitch the cord it won't cinch the bag up properly.

Once the sides are double-stitched, turn the bag rightside out to hide those seams in the inside (the worms won't mind the seams, they can't see anything). The bag part of this project is done!

Let's prepare our wood frame now.

Step 10: Cut the Wood for the Frame

All the wood for the frame is pine that is 2" wide by 1" thick. The lengths you'll need are:

4 pieces cut to 24" for the legs
4 pieces cut to 17.5" for the long sides
4 pieces cut to 14" for the short sides

At Lowes, where I purchased the wood, it came in 6 foot, 8 foot lengths (also longer, but those won't fit in my car). I bought 1 of the 8 foot lengths, which I cut into the 4 legs that are 24". I bought 2 of the 6 foot lengths which were cut into all the pieces for the sides of the frame.

I used a chop saw to make this go fast, but this could also be done with a circular saw or a even a jigsaw if you were good about clamping and keeping your cuts straight. However you choose, you must use your safety glasses and ear protection. Or, if you purchase the wood from a big box store such as Lowes or Home Depot you can have them cut the wood for you.

Step 11: Start Assembly of Wood Frame

Get your drill, your drill bit, philips head driver bit, 1 1/4" screws and wood glue ready.

The drillbit is for making pilot holes before putting in the screws. Trust me, you need the pilot holes. If you are cowboy-ing it and skipping the pilot holes, don't be mad at me when your wood splits.

The pilot hole drillbit should be about 1/8", or slightly thinner than your wood screws. You'll also need a philips head driver bit to screw in the screws with your drill. Special bits that make this all go faster are a magnetic quickchange driver that fits into the drill chuck and a quickchange countersink drillbit, which will slip into the magnetic driver and drill a pilot hole at the same time as drilling a countersink divit into the wood that will allow the screw head to go in flush. It pops out of the driver magnetically, so you can pop in your philip's head bit to do the screwing part, all without undoing the drill chuck. Totally worth it! Check it out in the detail pics.

Lay out 2 of the legs (24" long wood) and one of the long sides (17.5" long wood) as seen in the main pic. Wood glue needs to be connecting the pieces that are touching, so flip the side piece upside down to apply wood glue on its ends and flip it back over.

Step 12: Drill Pilot Holes and Put in Screws

After glueing, you'll need to strengthen these connections with screws. In this main pic, I have clamped my wood together and am measuring my countersink drill bit for the pilot hole. I don't want the bit to go all the way through, just about an inch and and a quarter, to match the length of my screws. After measuring, drill the pilot hole. If you don't have the countersink drillbit like me, you can use a plain countersinker bit, or even just use a large drill bit to make the divet for the screw head to be flush.

Now change to the philip's head screw driver bit and put your first screw in.

Then, repeat process - pilot hole drilling and screwing - on the other side of the same stick of wood. Now you should have a U-shaped frame, open on one end. Don't attach the other piece of wood  yet, read the next step first, before completing the rectangular frame! (Thanks to jwm.herbert, for this clarifying comment).

Step 13: Squaring It Up

Use a carpenter's square (really and "L") and see if you have a right angle on both of the wood legs. If not, you can still move the wood before the glue dries.

Don't have a carpenter's square? Find something else around your house that has a right angle. A large book will do. Or the corner of a table.

Step 14: Attaching the Other Side of the First Frame and Constructing an Identical Second Frame

Get another piece of your 17.5" wood. This is the bottom side of your frame. Rather than put it exactly at the ends of the legs, it made more sense to me to measure up 1 inch from the bottom of the legs. It seems like it will make it stronger, plus it keeps all that extra wood surface area off of the floor. If there is a bump in the floor it would be wobbly.

Smear glue on the end pieces, flip them over, stick them down, drill your pilot holes, screw in your screws and square it all up, just as you did for the other side.

Repeat this process to make an identical flat frame as is seen in the second pic.

Step 15: Attaching the Final Sides and Entering Three-Dimensional Land

Set your 2 flat frames on their edge, with the leg parts facing each other. You'll want to get them around 14" apart, so you can lay the 14" sides on top. Smear glue on the parts that touch, drill your pilot holes so they are going into the legs, not the ends of the other side part. Put your screws in at each point.

Step 16: Attach the Final Side Pieces to Complete the Frame!

Flip the frame over and attach the final 2 side pieces as shown.

Repeat the glueing, pilot-holing and screwing to put in the last 4 screws in, just as you did on the previous step.

Set it upright and you are done with constructing the frame!

Step 17: Bag Meets Frame

Install your handmade worm bag onto your wood frame. I did this so the side seams of the bag are diagonal to the wood frame. They fold over the top of the wood frame and get tucked to the underside of the wood.

The nylon cord is not really sewn into place, so it can slip around in the inside layers of the bag. Make sure it is right up at the edge. Cinch up your nylon cord as tight as it will go with your cord stop, making sure all of your nylon cord is under that wood lip.

While you are at it, cinch up the cord at the bottom of the bag as tight as it will go.

[Please note that it would actually make the most sense to paint the frame before installing the bag, but that is not the way I did it... I'll paint it later on and have to separate the worm filled bag from the wood frame. It works, but maybe you'll be smarter than me and do it once your wood frame is constructed. Most important is painting the lid though, because that is the part that experiences the most moisture.]

Step 18: Make (or Find) the Worm Bag Lid

Look around for a piece of wood or plastic that is around 20" x 15". If you use plastic you won't have to paint it, but you might not find a plastic lid that fits nice and looks good, so let's build a wood one!

I found some 1/4" thick plywood around the studio. If you find some that is thicker, that will work well too and it will be less likely to warp if you want to sit on it, or put a plant on top. But the thin lid is nice because it will be lighter weight and easier to open.

Measure out a 20" x 15" rectangle and draw a line.

Get a jig saw with a wood blade installed in it, put on your safety goggles and ear protection and make the cuts. Be careful not to cut your table or saw horse. Or your fingers.

Step 19: Sand the Edges to Avoid Splinters and Make It Pretty

I'm using a palm sander, with 80 grit sandpaper on it and going around the get rid of splinters and round off the corners. If you don't have a palm sander you can do this by hand with a piece of sandpaper. You might get bored before your corners are rounded off, but you could certainly sand any pokey wood splinters off by hand.

Step 20: Paint or Stain the Wood Parts, Then Put It All Together

I used some leftover deck stain. It is a semi-transparent oil paint that matches my deck. I think that any paint designed to come into contact with moisture would work. Exterior paints make most sense to me. I left mine unpainted for many months and the frame did not suffer at all, only the lid, which warped from the moisture.

After the paint dries, put the bag on, the lid and the Rubbermaid dishwashing tub underneath. Now you are ready to put your worms in their styling home.

Step 21: Ready for Your Worms (and Friends of Worms).

Put your red wiggler worms into the bag. I took part of one overfilling worm bag to put into this one - with worms, partially composted materials and all. I've always had pillbugs in my worm bins and bags, so you'll see a few of those hanging out. I asked a worm professional about them once and he told me that they are "helpers of the worms". They process some of the food and getting the microbial action going that is the actual food for the worms. So I'm happy to have them around, even if they gross some people out. When the worm bag is disturbed, they do tend to crawl all over looking a bit menacing to some folks, but they settle down and find hiding places in the compost, so you eventually don't even see them. They become the hidden helpers of the worms, so don't worry about it. Even if a few escape the bag once in awhile, they just die off. They can't live in our dry world.

Why don't you see worms at the top in the first pic? Because they hate the light (ultraviolet light kills them) so they quickly burrowed down into the food stuff to hide. I turned over the material and quickly took the second detail picture so you could see them. I have red wiggler worms or Eisenia Foetida, which are great for composting situations. Don't try digging up some common Nightcrawlers out of your yard for this type of composting, they will be unhappy because they like to burrow way down into the ground and are not happy feeding at the surface of the soil like red wigglers are.

Food for worms should be about 1 inch thick at the top of their bag. All types of vegetarian leftovers make great food - wilted lettuce, stale bread, dead houseplants, coffee grounds, tea bags, fruit and veggie peelings, apple cores, melon rinds, corn husks and cobs, rabbit and chicken poop and more. Don't feed them any poop from animals that eat meat, oily things, meaty things, citrus or super rotten stuff unless you want to endure the stink that will result.

To learn more about keeping worms, and to connect with like-minded worm people, I recommend visiting or joining up with the free and friendly community at

Step 22: Layer of Shredded Paper Is Important

After feeding the worms, I always sprinkle a layer of shredded paper on top. The worms also eat this stuff and turn it into compost, but more importantly, it keeps a balance in the system. I'm convinced that my diligent paper layer is why my worm bins and bags do not become anaerobic and stinky. I'm not sure if I really know what I'm talking about with that "anaerobic" talk, but I can tell you that this shredded paper layer method works great.

I also sprinkle water on top of the shredded paper periodically to keep things moist. Worms like water and air so I follow the practice that says you should keep the worm bedding as moist as a sponge that is wet, but not dripping. Another material I've used as worm bedding is coco coir, which holds the moisture just right. I'm told this material comes from the hull of a coconut. This is useful if you buy some worms by the pound and they don't come with their own bedding and compost. You can give them a bed of coir and then put food on top, then newspaper and they have a nice, moist world to squirm around in - one that does not compact down like newspaper does when it is put in too thick. Compacted newspaper does not let the air come in.

Step 23: Put the Lid on Top, Sit on It and Wait for Compost to Happen

This kind of works as a chair, at least for this picture. More often, I use it like a small table and set things on top of it, like plants, fish food and tools.

I feed this worm bag lots of plant clippings from the Farm Fountain pictured behind me. I also feed it rabbit poop, coffee grounds and lots of shredded paper.

Step 24: Find a Nice Place to Put It

Here is a lime green colored worm bag, living in the office of Catherine Girves, who was very instrumental in the development of this project. She is the director of the University Area Enrichment Association in Columbus, Ohio and she organized a crew of volunteers to construct many of these worm bags to "seed" our local community with the wonders of worm composting. Thanks Catherine!

Step 25: Harvest Some Compost

Hooray! Here is where your work will really pay off (and the unseen work of your worms). After a few weeks, open up the bottom by sliding the cord stop out and loosening the cord. Lovely, rich compost will come out. If you want more, squeeze on the bottom part or pat/hit it lightly and more will come out. If you start seeing some uncomposted parts or more than a couple of worms coming out, you should cinch it back up and wait some more weeks. Just throw the uncomposted bits and worms back up in the top of the bin.

Use this finished vermicompost to sprinkle on your houseplants and around your garden. You'll never need to buy that stinky steer manure or chemically fertilizers again!