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.

Comments

[huf123]

I use my own homemade stackable worm bin. I am interested in trying this, but I am curious. Have you had any problems with the compost packing down too much? I wasn't sure if the funnel shape would cause the compost to compact, which in turn would lead to odors. Great Instructable. Thanks.

[amyoungs]

Yes, the compost does compact at the end of the funnel, but since it is finished compost by the time it gets down there, it does not smell. The compacting is not usually too much trouble, unless I let it dry out too much, which makes it like a rock stuck in there. The way I have fixed this problem is to add a lot of water to wet it throughout. I poured a gallon of water through the top every couple of days until it soaked the bottom part enough to loosen it up and come out through the bottom. Now, in the winter when I know the air is drier in my house, I just add a glass of water whenever I put food in the top.

[Admirabilia]

I LOVE the continuous flow system and have set up several bags for friends... the problem that i have had however is that despite efforts to trap and deter mice they are a fact of life in our old apartment and they loved the worm bag as much as i do... they chewed a door into it and made it their new nest.... GROSS!

So, sadly my progress was for naught but i am going to post up a 'step can' tutorial for those who might have similar problems.

I am converting a steel stepcan into the new vermienvironment and its sturdy construction should keep out any little critters.

cross your fingers for me, but for those of you who also co-habitate with mice on occasion, this is fair warning. :(

[amyoungs]

That is not something I've had trouble with myself, so I appreciate your experience here. Great to hear you have invented the solution to the problem already! The stepcan conversion sounds to me as if it will provide perfect security against mice. The only thing I'd be concerned with would be aeration of the steel can. Do they make these perforated? If not, I'd recommend drilling small holes into the side of the can to allow air flow. Please do post a picture when you make it, I'd love to see it and hear how it works!

[whirlygeek]

So I have a fat ton of polyester fleece from my long ago "Oh, let's make Ren Faire Outfits" phase ... will that do alright, then?

[amyoungs]

I love the thought of the worms hanging out in a stylish, fuzzy fleece bag! It will probably be harder to sew, but it should work. As long as there is no tasty natural fibers in there, the worms won't eat it. Please post a photo when you get it done, I want to see it!

[liba_hunt]

So great instructable! I followed most part of it.
I am happy wormkeeper now very much thanks to this instructable which gave me courage to take them into a tiny apartment.

I thought I would briefly share my modifications too. My wormbin has wheels because I have to move things around in my little kitchen when I use my laundry machine. And with wheels it's convenient to have a "floor" for the wormtea bowl.
The frame and bag are really contrast colored so I did not want the fabric covering the rim. Solution was to use wire in a fabric tunnel and attach the wire to the frame in cornes only. It's not too perfect actually, when the bag gets heavy wire might slip over the screws holding it - needs an improvement.

[amyoungs]

Nice bin - wheels are a great addition! I also like the fabric pattern you picked because it looks like flowers and spider webs at the same time. The rim of your bag looks sturdy. I guess if it starts pulling away with weight you could just put a few screws right through the bag fabric into the wood. Maybe use some grommets to keep it from tearing. Maybe it will hold just fine as it is, too.

Thanks so much for posting the pictures of your modifications for others to see here!

amy

[shabbysquire]

Great set-up, and I like the easy continuous flow design. This beats stacking systems as you have to 'dump' & 'sort'.

[fraggle313]

Hi, the worm bin bag looks so cool. I was just wondering if it can be used outdoors. I'm from Australia and was wanting to put under my verandah outdoors. Do you have any suggestions on other materials that i can use or if the felt will still work?
Thanks great job!

[amyoungs]

It should work outside if it does not freeze where you are. The worms also don't like the direct sun baking them. The felt should hold up outside because it is plastic - polyester that is made from recycled plastic bottles. I have not tried it outside myself though. For my design I was inspired by a product called the "Australian Worm Swag" which is a huge flow through vermicomposter made of plastic that hangs from a tree. You might check into that too, to see if it would work for you or if it gives you some ideas for making your own hanging version.

[fraggle313]

Thanks for your advice. It definately doesn't freeze here about 12 degrees (53 farenheit) lowest for about a week during winter. Probably an issue other way 30+ degree (86 farenheit) and 90-95% humidity during summer months but that is about 5 months of the year. I won't be putting directly in sun but the humidity may be an issue. Is it best to just keep it moist?

[Pizzapie500]

LOL so I tried a mini version of this with a shirt, TOTAL FAIL! The worms ate right through the shirt, luckily I put it inside a rubbermaid box so it didn't get everywhere.

[amyoungs]

Yeah, they love to eat cotton, wool and rayon (wood based). I guess if you use a polyester or acrylic shirt it might work, though!

[gserrano701]

Fantastic idea, job and instructable, makes me wand to do vermicomposting at home.

[du fox]

This is an AWESOME instructible, Kudos for sure!

[denine]

This is really cool - we bought a composter last year and have it out in the yard, but I looked into using worms first. Unfortunately, all of the user reviews of the pre-made versions said the worms were drowning in the liquids that pooled at the bottom. I love that everything drips down and if the worms come out, they land safely in the bin!
http://www.weknowstuff.us.com/

[kadewei]

Thanks so much for this Instructable! I made one using a very sturdy IKEA Antonius stand for laundry bag (7$ or 5.5 Euro without the bag) and an IKEA Trygg serving bowl (4$ or 2 Euro) at the bottom. The outside bag is made of a heavy duty disposal bag made of white woven Polypropylene. I find white nicer looking than black, and I guess that in summer it will keep the worms cool. But white lets through too much light for the worms, so I lined it with an identical bag made of landscaping fabric, which is black woven polypropylene. The top corners of the black lining are closed with duct tape so light is completely blocked out. Polypropylene is a food safe non toxic plastic, and the woven form can be sewn like very fraying fabric on a normal sewing machine. The worms are still alive, so I guess it lets through enough air. (Top inside view on the right. On top of the worm bag is a tray with seeds that have not yet sprouted)

[rkimedes]

I did the same thing with the Antonius, but I didn't want to have to take stuff off of the lid to use it, laced it to the inside of one of the antonius' drawers.

[amyoungs]

This sounds very interesting. What are the drawers like? I'd love to see what yours looks like. Might you post a picture for us? -amy

[rkimedes]

I tried, but it didn't work :-) I documented my deviations, though...
http://rkimedes.livejournal.com/370812.html

[Anianna]

Oooohhh, I love this modification. How has it held up over time?

[amyoungs]

Fantastic worm worm composting drawer design! I love your hacking of the IKEA drawers combined with the worm bag. The recycled Huggies box is also a great idea - thanks for sharing your pictures of it on your blog. -amy

[nachobobs]

If you were to make the bag out of a porous material such as cotton,could you then in fact catch all the liquid fertilizer as it is formedor use a litre of water over the worms once a week to create nutrientrich liquid on demand? 

[amyoungs]

Hi Nacobobs,

Even though the material is made of polyester felt, it is still very porous and indeed water can flow through it. I have poured water into the top and retrieved the resulting compost tea from the tub below. I have not done it very often, but it would be interesting if someone on this comment list knows if it can be done every week and continue to provide nutrient-rich fertilizer. Maybe you will try it and let us know? BTW, I would not try making this out of cotton, since worms will eat it!

-amy

[sparkleponytx]

I was wondering about this same thing--the "juice" or "tea" that comes from the bin. I bought a worm bin--the layer type. It has a spigot at the bottom which I leave open with a can to catch the tea which leaks out almost daily. I was wondering, am I doing something wrong or what? And how will this bag not leak? I love the idea of the bag. I am going to give it a try.

[amyoungs]

The leaking is normal, and it is a plus, since it is just the kind of nutrients that plants, lawn, trees, want to drink in their water. I do notice that the leaking happens more in the summer and during humid times. Depending on where you live and where you place your worm unit, you might never need to add water. In Ohio I only need to add water to my indoor bin bags during the winter months. Since the plastic worm bins with the spigot do not have a chance to aerate through the sides, they do tend to have more liquid coming out of the spigot. I have one of these too, and I never need to add water to it.

[danielrudd]

very well done. thanks for taking the time.  Do you think a giant version of this that was more oblong would work?  

 

[jwm.herbert]

Thanks!
I have a couple of comments for improvement:

It's a little confusing when you say, "Then, repeat process - pilot hole drilling and screwing - on the other side."

I thought you meant do the other end of the frame -- not just the second screw on the same end!


Drilling and putting the 2nd screw in just seemed so natural to me...  that I went ahead and did it...   and then read, "repeat process on the other side."

At that point, I thought it meant, Add the second piece of wood to the other side, and do the same thing.... which I did.
Thus, I ended up with a perfectly symmetrical rectangular frame (thinking this was how it was supposed to be)...

Whoops!   I didn't realize my mistake until it was too late.... Now my frame won't rest levelly on the floor!  (My mistake -- I'll find a way to level it.)


Perhaps it would be helpful for others - if you could change the wording to:

"For your second screw, repeat the process-- drill a pilot hole with countersink, then screw the second screw in.

After this:
You now should have a U-shaped frame that is "open" on one end.
Don't attach the other piece of wood yet!!   Read the next step *before* completing this rectangular frame."

What do you think?
And thanks for the awesome instructable!  I can't wait to start composting!

[amyoungs]

Thanks so much for your helpful clarification. I took your advice. Thanks also, for posting it on your alternative energy blog site!

[vee77]

 I just made a worm compost using your instructable concept.  I am new to composting and thought this was very asthetic.  I used a friends donated hamper bin legs, a $10 black canvas laundry bag. It had shoulder straps so I just flipped it cinch-side down, tied the shoulder straps around one side and knotted the excess straps to the other side for tension to hold the legs up.  I cut a flap opening at the top and made a little string knot to open and close it.  Reinforced the knots, holes and bindings with electrical tape, just to use electrical tape and keep holes from splitting.  I'll get a picture up later. Great instructable.

[amyoungs]

It sounds like your hamper bag is pretty inventive. I'd love to see a picture, when you get a chance. Happy vermicomposting!

[roddy272]

 how many worms can that bag hold before u have to move some of the worms

[amyoungs]

 The great thing about these worms is they will reproduce based on the food and space available. After that, they reach an equilibrium and you don't need to worry about overcrowding. If you do want to split them off into another bin, or to give to a friend to get their bin started, you can be assured that they will always reproduce to full capacity again, provided they are well cared for. 

[roddy272]

 the worm bin bag on the instructable  how many worms can it hold

[amyoungs]

 I've never counted... but I would estimate 1 to 2 pounds of solid worm mass.

[skarfac3]

how often do you feed them? 

[amyoungs]

 Once a week or so. I give them about 1/2 to 1 pound of food + shredded paper on top of the food. Even if I'm gone for several weeks they do just fine as long as I put extra water in there to keep it moist.

[jmm322]

Here's mine - we re-purposed a plant stand. Since the picture was taken (a few weeks ago) we've replaced the lid with a heavy saucer from a terra-cotta plant pot, which seems to close the gaps at the top a little better. It will have a plant living on top of it again soon. I'm looking for some help with a fruit fly problem. They're everywhere. We had a few of them before making the worm bin but they're much worse now. We're keeping the top layer nice and clean, shredded paper. Any ideas on how to get rid of the flies? What is a natural predator for fruit flies?

[ton_yun_mui]

 I found microwaving scraps for a 90 seconds before putting them into my bins prevents fruit flies from showing up