Worm Composting: How to Make a Wormery

, written by Benedict Vanheems gb flag

Worm composting

Wonderful, wondrous wiggling worms are the starting point to healthy soil and awesome compost. A healthy compost heap is full of them, but there is another way to turn kitchen scraps and weeds into nutrient-dense goodness: by using a wormery.

Wormeries, or worm composters, use special composting worms to turn kitchen waste into nutrient-dense compost and liquid fertiliser. They don’t smell, take up very little space, and are a great way to introduce children to the wonders of worms. Use one as a standalone composting solution for courtyard or balcony gardens, or as a complement to a traditional compost heap or bin.

How a Wormery Works

A wormery is typically made up of at least two compartments. The bottom compartment collects the liquid, which can be drained off to use as liquid feed for your plants. The top compartment is where the worms live and where you’ll put your kitchen scraps to feed them. This is also where your compost, or worm castings, will be made. A lid keeps everything from drying out or becoming flooded by rain showers.

Two compartments will work, but using a third compartment makes it easier to collect the worm compost.

Holes in the bottom of both the middle and top trays ensure that the liquid produced by the worms can percolate down into the collection tray at the bottom. And once a tray is full, the holes enable worms to migrate up into a new tray, so that compost from the vacated tray can then be harvested.

“Composting
Worms will make short work of kitchen scraps, turning them into nutritious fertiliser for your garden

Making a Wormery

Choose trays or boxes to make your wormery with. We’re using plastic boxes about about 16x20in (40x50cm) and fairly shallow at just 8in (20cm) deep. You’ll also need a simple plastic water barrel tap, a drill and drill bits, and a lid for the top tray.

You’ll also need some worms of course. Don’t be tempted to use worms from the garden – they’re great for tunnelling and improving your soil, but not so quick at composting. You can order composting worms online. We’re using a lively mix of European nightcrawlers and tigerworms capable of eating twice their bodyweight a day!

So let’s assemble the wormery, starting with the bottom tray. Carefully cut out or drill a hole to snugly fit the thread of the faucet. Fit it as low as possible in the tray so that liquid isn’t left at the bottom when you drain it off. Screw it tightly into position then secure with the back nut. You can raise the wormery up on bricks to make it easier to drain off the liquid into a container.

“Homemade
Using three trays makes it easy to remove the worm castings from your wormery

Drill quarter-inch (half-centimetre) holes approximately every two inches (5cm), right across the bottom of both top trays. Drill a single row of holes near the top of the two trays at the same size and spacing. These holes will help to improve airflow, creating a healthier environment for your worms.

Now’s the fun part – time to add your worms! Start with a three-inch (8cm) layer of bedding material. You can use compost or coir fibre, dampened a little to make it nice and comfortable for your worms. They’ll soon bury themselves into that lovely bedding.

Once you’ve added your worms, add a layer of kitchen waste – no more than a couple of inches (5cm) to start with. You can also add a layer of burlap to keep them extra snug. Wait a week before adding any more food, so give the worms time to settle into their new home.

Worms like moist, warm conditions, so keep your wormery somewhere shady and as close to room temperature as you can. They don’t like to be frozen, so move the wormery indoors for winter – into a garage, outbuilding or utility room is ideal.

“Kitchen
Feed scraps and peelings to your worms

Looking After Your Composting Worms

Add food a little at a time to the top of the compost. Avoid adding too much food at any one time, as this risks creating an odor that will attract flies.

The worms will digest any vegetable kitchen scraps, including coffee grounds, that you’d normally add to compost, but avoid meat or animal products such as cheese which can attract flies. Go easy on citrus peel and alliums like onion and garlic too, as large amounts will make conditions too acidic for your worms. You can also add small amounts of weeds and leaves, as well as shredded, non-glossy newspaper or torn-up cardboard.

Once the top tray’s full, swap it round with the empty middle tray and start filling that instead. The worms will migrate up through the holes to where the food is, leaving the full tray empty of worms and ready for collection. Repeat this process each time the active tray becomes full up.

“Worm
Worm tea or worm wee makes a nutritious liquid feed for your plants

Using Worm Compost and Worm Wee

The worm compost, known as worm castings or vermicompost, makes a great all-purpose soil conditioner, or add them to your own potting mixes to give them a nutritional boost.

Drain the liquid off from the bottom tray whenever it collects. This nutritious liquid, often known as worm tea or worm wee, is a super elixir for your plants. Stir one part of the liquid into ten parts water before using.

And there you have it – a superb, home-made wormery that will keep you in wonderful worm castings and lovely liquid fertilizer. If you already have a wormery, tell us about it! What do you do with all that goodness and how have your worms benefited your gardening? Let us know down below.

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Comments

 
"je reste a Montreal dans le Canada. Cette année, j'avais tellement de vers que j'avais de la difficultés a les nourrir. Celui qui me les a vendus m'a dit qu'il en avait mis dans son potager en contenant et dans ses pots a fleurs. L'hiver, les vers se rassemblent au centre du contenant et , Semble-t-il, sont en pleine forme pour l'ete suivant. Je m"en suis gardé dans le garage mais ceux en trop sont enfoui dans les contenants du potager. A voir, a l'été qui vient."
Marty on Tuesday 10 September 2019
"Quelle bonne idée! "
Ben Vanheems on Wednesday 11 September 2019
"I want to try this! I live in the Phoenix, AZ area (Zone 9) and am wondering if there are any special instructions due to our heat. I'm not too concerned about the fall, winter and spring. Primarily just the summer when it is above 90 and quite probably above 105 for an extended period of time."
Melissa Rightmire on Saturday 28 September 2019
"Yes, the heat could prove a problem. I would make sure that your wormery is in deep shade for the summer, so it doesn't heat up and cook like an oven from the direct sun. You could put several layers of burlap over the whole thing by way of insulation and additional shade too. It may be necessary to spray the ingredients with water from time to time, if it gets very hot and dry, to maintain a moist (but not wet) environment for the worms. If it looks like they are struggling then I'd consider moving them inside for the height of summer."
Ben Vanheems on Saturday 28 September 2019
"Maybe someone can help me. I have just inherited a second-hand can-o-worms wormery. I bought a starter pack including coir, feed and of course those beautiful little wrigglers. I set it up as per instructions, but they keep migrating down to the sump tray. Every morning I go out there are move them all back to the "nice" coir bedding. They aren't eating anything (neither worm food supplied nor small amount of kitchen waste). I have checked that it isn't too wet/dry. I am keeping in in the shed. Please, what am I doing wrong? Your thoughts would be much appreciated."
Maria Culmer on Friday 4 October 2019
"Hi Maria. Are there new holes in the bottom of the tray or is it damaged in some way that they are escaping? I can't imagine it is too light in the shed, so that can't be the problem. It may be worth contacting can-o-worms directly to seek their advice, as they will be familiar with the model you have. It does sound like you're doing everything right though."
Ben Vanheems on Monday 7 October 2019
"Do I need to put bedding material into each tray? Or do I just fill the upped empty tray with veggies only? I forget, can they have cooked veggies, pasta etc non meat of course. Thanks. PS. I think my shed may be too cold, if I wrap them in bubble wrap will that fix the problem?"
Mel Eaton on Sunday 20 October 2019
"Hi Mel. No, there's no need to put bedding into every tray - just the initial tray you begin with. Cooked food can be added in small quantities, but the majority of the food should ideally be fresh - think peelings, coffee grounds, limp leaves, old carrot tops, banana peel etc. Your shed may be too cold. It's best to move the wormery into a cool room indoors if you can - or at least a porch or garage or similar. Temperatures close to freezing won't do the worms any favours. In nature they'd be able to go deeper to avoid freezing, but in a wormery they can't. Bubble wrap may work, but best to bring it inside if you're able to."
Ben Vanheems on Monday 28 October 2019
"Can I ask where your bins are from? Having trouble finding something similar. "
Randy on Sunday 12 January 2020
"These were just bought off Amazon - basic storage boxes. You could try somewhere like www.containerstore.com"
Ben Vanheems on Monday 13 January 2020
"The composting worms are actually eating the fungi and bacteria that colonizes the surface area of the decaying plant material. The stuff should be just damp enough to hold its shape when you squeeze it, but not drip or fall apart. Add shredded damp newsprint or cardboard torn in small pieces to make more surface area for the fungi. You will not be able to see them actually "eating". The process works faster when it is warmer (70-80F) and much slower when it is cooler(50-69F). Most composting worms for home use, species Eisenia or Red Wigglers, can't tolerate freezing and barely survive at temps under 50F. Never release composting worms into the environment, especially near woodlands! Forests need the micro fungi and bacteria networks in the soil around the tree roots, the same fungal networks which the compost worms eat. Earth worms do serious damage if they are released into forests!"
Sandra Sweeney on Saturday 15 February 2020
"Hi Sandra. Many thanks for sharing that insight, it's appreciated."
Ben Vanheems on Monday 17 February 2020
"I am thinking of doing this, and I know you said you got the bins from Amazon. Could you please give me rough dimensions, I am trying to work out where to put the bins. Also, I live in Upstate New York, right by Lake Ontario, so the winters can be brutal! Will I need to keep the wormery indoors in the winter and do the worms sort of hibernate? Or do I need to keep feeding them all year round?"
Jadis on Thursday 12 March 2020
"Compost worms live naturally in the duff layer on the surface of the soil. They do not make burrows, so do not have the ability to go below the frost line in the normal soil. Upstate New York has not had any native earth worms since before the great glaciers, so typical compost worms will die if exposed to "winter". They will do best at temps around 50F, slower than summer temps, but still living and eating less. You should keep feeding them kitchen waste in reduced amounts. Do not let them freeze!"
Sandra Sweeney on Thursday 12 March 2020
"Hi Sandra. Many thanks for that useful comment. Jadis - Yes, the worms will need bringing under cover for winter, so they don't freeze. A minimum temperature of around 50F is ideal, as Sandra suggests. The dimensions of the bins are around 15x19in and 8in deep."
Ben Vanheems on Monday 16 March 2020
"Great, thank you Ben and Sandra for the information. Once this crazy lock down situation is over, I will sort out the bins and start my wormery"
Jadis on Wednesday 18 March 2020
"Something to look forward to Jadis!"
Ben Vanheems on Thursday 19 March 2020
"Can you provide the link which you purchase the box? Thank you so much!"
Jasmine on Sunday 12 April 2020
"Hi Jasmine. The boxes I used are of a good dimension, but they weren't a perfect fit. There is a gap when the bottom of one tray slots into the top of another, meaning rain can get in. Therefore the specific make I used isn't to be recommended, though the principle remains the same. It may be worth searching for something similar, but checking with the sellers that they do in fact sit together with a snug fit."
Ben Vanheems on Monday 13 April 2020
"Hi Ben, Have just purchased 500grams of tiger worms which will be perfect compost for my veg patch !! I know you have already been asked but can you recommend / send a link of what plastic box is best suited ? Many Thanks"
Jack Chaplin on Monday 4 May 2020
"Hi Jack. The plastic boxes I bought turned out not to be a good fit - they didn't fit snugly, leaving a gap at the top where they fit together, which lets the rain in. Therefore I can't recommend a suitable plastic box, as the one I used was far from ideal. I would suggest searching for 'storage boxes' but getting in contact with the supplier to check that they are indeed a snug fit, before you order. Good luck with your wormery. It's a very satisfying project."
Ben Vanheems on Tuesday 5 May 2020
"Good content, i have followed the video and instructions and bought my starter packs from Yorkshire Worms - excellent service, I also bought 3 x 50L black boxes from Really Useful Boxes which appear to fit quite well, i have placed my wormery in a sheltered space between 2 garden sheds and will rig up a roof over it to protect from rain. This is my first attempt, lockdown sanity saver - what else was there to do???"
Donald Macleod on Monday 22 June 2020
"Hey Donald. Hearty congratulations on getting your wormery started - that's great to hear. And well done on finding boxes that fit neatly too. Good luck with the whole project."
Ben Vanheems on Tuesday 23 June 2020
"Do I keep adding garden like to keep things healthy?.certainly didn't appear to do harm. Have had wormery for 10 years , and get all my potting compost ,and feed, and make sure 25% of feed is shredded paper , and lightly water every 4 weeks!"
Bruno Brown on Friday 19 February 2021
"Hi Bruno. Thanks for that tip - I guess the shredded paper keeps everything open and well aerated."
Ben Vanheems on Sunday 21 February 2021
"Thanks for the inspiration, I have purchased B grade (colour) Euro boxes + lid from Solent Plastics which look really cool as the colours are mixed and look tie-die (code BEG64/17 if anyone is interested). Drilled holes as advised and works really well as they stack nicely. 500g of compost worms + coir + food from Wormcity, first few days were tense, suddenly realising it's parenthood all over again - but you have a mixed bag of babies, some with attitude, some who just want to escape and others who are shy, docile or munchers (best type). I'm now on week 2, had a few deaths in the family due to escapees b My only advice I can provide is... - As recommended in the article I used hessian to cover the worms in the box (that was my interpretation) to find I had a few worms entwined in the weave of fabric and nearly garrotting themselves so decided to opt for a layer of thin brown card instead. - If you put your wormery in your garage make sure you you sweep the floor first and put tarp or plastic sheet down, otherwise you'll wake up the next morning to find a handful of dessicated worms on the floor. And no, you cannot revive them by 'just add water'. On the above note, the worms do settle and less inclined to escape after a few days, I think the 24 hour journey via postal / courier service + new accommodation up-scuttles them. "
Mark on Tuesday 20 April 2021
"Hi Mark. That's really helpful of you to share your experiences, thank you. It's great to hear you've found boxes that properly stack - that's great! I hope your worms are settling in nicely and will do you proud."
Ben Vanheems on Wednesday 21 April 2021
"When you change the top tray with the middle tray, do you add coir to the new top tray or just the food scraps?"
Magie on Monday 20 September 2021
"Just the food scraps Magie."
Ben Vanheems on Tuesday 21 September 2021
"This looks good, do you mind me asking where you got the storage boxes from ?"
Geoff on Wednesday 6 July 2022
"Hi Geoff. The boxes I bought turned out not to be ideal as they let in a bit of rain at the edges. However, another reader, Mark - see his comment above - suggest the following: "I have purchased B grade (colour) Euro boxes + lid from Solent Plastics which look really cool as the colours are mixed and look tie-die (code BEG64/17 if anyone is interested). Drilled holes as advised and works really well as they stack nicely.""
Ben Vanheems on Wednesday 6 July 2022
"I found this website very useful for me. I was about to set up my wormery and order my worms but think perhaps I should wait until Spring when the frosts have gone before I buy the worms. Thank you fir all the information."
Marian on Sunday 16 October 2022
"So pleased you found the article useful Marian. Best of luck with your new wormery."
Ben Vanheems on Monday 17 October 2022
"I am hoping to start a wormery soon- when the frost goes, so looking forward to putting all the great advice into practice. Clare"
Mrs A M C KEDVES on Wednesday 25 January 2023
"That's really great to hear Clare. I hope it all works out well and the worms settle in. :-)"
Ben Vanheems on Wednesday 25 January 2023
"Fabulous idea; a few questions. How long would it take to harvest the worm tea, and also, how often should it be given to plants in order for them to benefit? Thanks for making gardening and growing so accessible to those of us with absolutely no experience. I can't begin to tell you how grateful I am!"
Katy on Tuesday 6 June 2023
"Hi Katy. The frequency of worm tea harvesting really varies with the number of worms, material they are consuming and the conditions they are in. Sometimes little to no tea is produced because it is quite warm/dry. I don't think you will ever produce enough worm tea to use it very regularly, so just use it as a boost when you have it. But if you did have lots, I probably wouldn't apply it any more frequently than, say, once every two weeks."
Ben Vanheems on Tuesday 6 June 2023
"Hi Ben, I wish you hadn't still got this video on Youtube. I came across it 3 or 4 days ago, was excited and inspired and ordered the same boxes you used. I now have a wormery that is useless and a lot of hungry, wriggly worms that might escape tonight. Perhaps you could do a new video using suitable boxes or at least put a warning on the old video. I love your work and I love your videos so am a little surprised and disappointed to find this doesn't work. Also, I watched a video with silver/steel coloured criss-cross metal arches. Where did you get them from? I spent a long time trying to find them online but with no luck. I really like the look of them and am looking for an arch to cross the path between my veggie beds. Many thanks Beatrice"
Beatrice Breedon on Friday 23 June 2023
"Hi Beatrice. When I made the video I purchased some storage boxes which I thought were suitable. They were in every way except that they didn't quite fit snugly at the top, leaving gaps. However, this wasn't a problem for the video itself - it wasn't obvious and the project and the way it was presented was still sound and correct. I have subsequently advised on sourcing different boxes to the ones I found when asked about this - see the above comments. However, I think you are right that I should at least pin a comment with the original video, advising viewers to make sure they source snug-fitting boxes. I will be sure to do this. I'm so sorry if your worms have escaped. The arches are from Agriframes, a UK company. They are their Elegance Round Garden Arch."
Ben Vanheems on Friday 23 June 2023
"Many thanks for your speedy replyXQKPX, Ben. My worms haven't actually escaped yet I'm just concerned they may do overnight before I can resolve the situation. :0)"
Beatrice Breedon on Friday 23 June 2023
"Hi Beatrice. I hope they haven't escaped just yet. If conditions in the wormery are friendly to them, the worms should stay put. Thank you for your comment though, and I hope you manage to resolve the problem. :-)"
Ben Vanheems on Sunday 25 June 2023
"Does it have to be kitchen scraps or can things like soft garden pruning and lawn clippings be added if you don't have enough kitchen scraps that week to keep your worm count up?"
Natalie on Friday 28 July 2023
"You can certainly supplement kitchen scraps with soft green materials like lawn clippings, no problem."
Ben Vanheems on Wednesday 2 August 2023
"I think I'm going to give your wormery a try, but I have a question: Do you ever have to add water to the compartment where the worms are working, or do the kitchen scraps contain adequate moisture? If you do add water, how much? "
Tim Fikse on Tuesday 14 November 2023
"I have never had to add extra moisture - there's usually enough in the kitchen scraps etc that are provided. That said, if in a warmer climate with drying winds, you may occasionally have to add a little extra moisture if the materials added start to feel a bit dry. In this instance I would probably look to mist-spray the top of the wormery from time to time, just to keep humidity up a bit. But as I say, I've never had to do that."
Ben Vanheems on Tuesday 14 November 2023

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