Worm Troughs

Inside a Worm Trough - Food is always added to one side

“Create masses of worm castings, and breed up masses of worms, with a worm trough!”

A worm trough is a large and long container which allows for a different system of feeding to a worm farm. Worm troughs can breed up a large population of worms who can process a large amount of material. A properly managed worm trough will allow you to access fresh castings any time, and to feed the worms just as easily as with any worm farm.

Benefits:

  • Creates lots of fertiliser
  • Breeds an abundance of worms
  • Easy to manage
  • Cheap to make

Materials:

  • Structural timber
  • Timber slats or fibre-cement boards
  • 1 x Sheet corrugated galvanised roofing (800mm x 3m)
  • 6 x galvanised roofing screws
  • 6 x galvanised bolts
  • Galvanised nails
  • Galvanised screws
  • Old rubber hose
  • Composting Worms

Jump to:

How to Make a Worm Trough
Materials
Designing
Constructing
How to Use a Worm Trough
Starting a Worm Trough
Feeding a Worm Trough
Using Worm Castings
Integrating a Worm Trough
FAQ
What’s the difference between a worm trough and a worm farm?
What other materials can I use to make a worm trough?
Do I need to flush my worm trough?
Related Articles
How to Worm Farm
Encouraging Earthworms
Worm Towers
Worm Bags
Worm Stations

How to Make a Worm Trough

A worm trough, made from corrugated steel, timber and fibre cement board

A worm trough, made from corrugated steel, timber and fibre cement board

Materials

It’s important that you base your design on the materials available to you. I had a spare 3m sheet of zincalume corrugated steel, and leftover offcuts of hardiplank fibre cement board, and I based my design entirely on those. If the sheet metal you choose is more or less than 800mm wide, you will have to modify your design. Use mine only as a guide.

Designing

Whip up a sketch to help you design your worm trough

Whip up a sketch to help you design your worm trough

 

  • Flex your sheet metal into a ‘U’ shape and measure the width. Design three frames that will hold the sheet metal in this shape. I soon discovered that within the same frames I could fit an additional trough!
  • Design two lids, with bolts connecting them to the frames. The lids don’t have to seal shut, in fact that will prevent airflow. The lids are there to keep out birds, rats and heavy rain.
  • Design side panels to close the trough at both ends, again to keep predators out, but also to stop worms and materials falling out.

Constructing

Six roofing screws secure the sheet metal to the frames.

Six roofing screws secure the sheet metal to the frames.

  • Assemble your 3 frames first, using galvanised wood screws, and flex and fit your sheet metal in place.
  • Fix the sheet metal in place by drilling through the top inside of the trough into the frames. Don’t drill through the bottom of the trough.
  • Cut lengths of old rubber hose and slice them open lengthways (using strong scissors). Fit them over the exposed edges of the sheet metal. This will allow you to work with your trough without cutting yourself.
  • Assemble your 2 lids and bolt them to the frames, making sure they open and close easily. Remember wood can expand when it’s wet, and a perfectly fitting lid can jam. Allow plenty of room for expansion.
  • Fit your 2 panels, one to either end of the trough to close it.

Position your worm trough somewhere shaded.

How to Use a Worm Trough

Starting a Worm Trough

  • Lay down a thick layer of collapsed cardboard boxes (plain, not glossy) at one end of your trough. There doesn’t seem to be a limit as to how thick this layer can be (I’ve added 16 layers and they were completely consumed!). Moisten the cardboard, but there’s no need to saturate it.
  • Get a batch of composting worms (and their castings) and dump them on top of the cardboard, right at the end of the trough. They will gradually retreat into the cardboard bedding.
  • Add some kitchen scraps where the castings end, not on top of the castings.
  • Cover the kitchen scraps and castings with a layer of wet newspaper or cardboard.

Check your worm trough regularly, to see that the worms are eating the scraps. Don’t flush your trough with water, only make sure you keep the newspaper/cardboard covering damp.

Feeding a Worm Trough

Worms move laterally as food is always added to one side.

Worms move laterally as food is always added to one side.

  • You can feed worms just about anything you would put in a compost bin. Kitchen scraps, newspaper, plain cardboard, tea bags, coffee grounds, crushed eggshells, young weeds and hair clippings are all common waste products which worms can eat and turn into fertiliser. However, they will not eat meat, dairy, bones, onions or garlic (chuck these in the compost!). Also be careful not to add too much grass clippings or chicken manure as these can overheat a worm farm and kill worms.
  • Always add food to the end of the castings, so that the worms are encouraged to move along the length of the trough. As the bulk of the worms move along, their castings are left almost completely vacated (especially if you allow the rear to dry out).
  • Always add a bit of soil to the scraps (a handful is plenty). This inoculates the scraps with bacteria which will help break down the scraps. Soil is also an important part of a worm’s diet – they swallow a bit to help grind up and pass the food they eat. Without soil they will become sluggish.
  • Always replace a covering of wet newspaper or cardboard so that the environment remains moist. Worms are capable of distributing moisture around their environment, but without a covering they won’t go to the surface and you’ll have uneaten scraps interfering with your system.

Using Worm Castings

  • As the worms are encouraged along the length of your worm trough, they will leave their castings behind. From this end you can take castings any time.
  • I recommend using castings for seedling trays, as almost anything will sprout in worm castings. In your garden worm castings are an excellent boost, and you can continuously add castings to pot plants (try keeping a few worms in larger pots to mix and aerate the soil).
  • Be considerate when adding composting worms straight to your garden. Their natural environment is in the moist leaf litter under trees. On naked land they will likely die. If you want to introduce worms to a garden bed, try making a worm tower.

Integrating a Worm Trough

You can use your worm trough as part of a system of waste management. For example, you can compost all your scraps and raw materials in a compost tumbler, then feed a portion of the partially-cured compost into your worm trough (the rest can be added to a cardboard compost bin to finish breaking down). Worms will happily eat this mix, along with the cardboard you lay down as a bedding.

Also, as your worm population reaches ‘teeming’, you can begin diverting worms into a worm tower or worm stations, to populate your garden. Once your garden is teeming, you’ll have the best soil in the world!

Frequently Asked Questions

What’s the difference between a worm trough and a worm farm?

Worm farms require emptying, rotating and stacking (depending on the design), and can only support about 20,000 worms. A worm trough can be added to and taken from easily, and can support a huge amount of worms, which enables it to process a lot more material.

What other materials can I use to make a worm trough?

Look around at what you already have. You’ll be surprised what can be made out of scrap, with a bit of thought and design. Try to use second-hand materials where you can.

  • Any kind of sheet metal can replace the corrugated steel I used, but try to avoid any that has paint, or will corrode quickly.
  • Any structural rot-resistent wood can replace the treated pine I used. If you’re going to use treated pine, I recommend coating it with raw linseed oil, to waterproof and seal it. Chemicals won’t leach so readily from this treatment.
  • You can also dig a trough shaped trench in the ground and lay a plastic liner down, to make an in-ground worm trough. Be careful not to puncture the liner when you’re digging in there.
  • You can make a worm trough out of an old bath tub or refrigerator. For a bathtub worm farm you’ll need to create some lids to cover it. For a refrigerator worm farm you’ll need to drill holes through the seal (or the door) to allow air flow. You may also want to drill a drain hole for excess moisture.

Do I need to flush my worm trough?

No. Flushing only dilutes and washes away nutrients from the castings. It’s fine if you have a specific use for the liquid, but the remaining castings will not be as rich. If you only ensure that there is always some wet newspaper or cardboard covering the materials in your worm trough, you won’t have a problem, and the castings will be the richest in the world!

Related Articles

How to Worm Farm

“Let the worms do the work, with worm farming!”

Encouraging Earthworms

“Earthworms are a gardener’s best friend!”

Worm Towers

“Create an instant home in your garden for worms, with a worm tower!”

Worm Bags
Worm Stations

 

12 comments on “Worm Troughs

  1. I like this …. I have been looking about African Nightcrawlers. I was reading they can get up to 8′. Ok I have question how do you separate the worms from the soil?

    EzE

    • Hi EzE, good question. Worms are ‘photosensitive’ and will burrow down to get away from sunlight. If you spread worm castings (and worms) over a sheet of plastic/cardboard, the worms will retreat and you can scrape off the top 2cm or so. You’ll see them retreat again, and you can continue scraping until they’ve got nowhere to go, at which point you’ve probably got all the castings you should take. Another method is to feed them always on top or to one side, and if enough height or length is achieved, the worms will have moved away from their original castings and you can take them. Hope that helps!

    • Hi Ben, the deepest ive seen is about 30cm with worms still at the bottom, but I’ve heard of much deeper systems. The worms will constantly tunnel through the material and aerate it, so long as you’ve allowed for good ventilation (don’t cover the whole surface with wet newspaper – leave gaps!), and good drainage.

  2. I am looking into using this system because I am tired of separating the worms from the castings.
    How long does this trough need to be to ensure the worms are out of the starting end of the trough?

    Thanks for the info on this.

    • Hi FireMed, no matter how long your worm trough is, there will always be some worms left amongst the castings. I’m not sure why, but somebody once told me it’s the adolescent ones who venture to the surface, while the mature ones hang around the castings more. If you’re using the castings directly in your garden, it’s fine to include some worms if the garden is mulched and soil kept moist. Their natural environment is around the base of trees. If you’re drying/storing the castings, you’ll have to screen the worms out – here’s a cool homemade harvester someone’s invented: http://whatcom.wsu.edu/ag/compost/pdfs/lowcostwormcastingharvester.pdf

      Hope that helps. Let me know how you get on.

    • Actually FireMed, I just remembered something. A couple years ago I neglected my worm trough and the contents almost completely dried out – the worms had all retreated to the bottom centre where the last moisture remained. I’m thinking, if you’re feeding to one side, keeping only that side covered and damp, the castings at the other end should start to dry out, and the worms should retreat away from that. It might be important to slope your trough so any moisture moves away from the castings. Whaddya reckon?

      • Makes sense. I was mainly wondering how long the tough would have to be to give it time to dry out at the starting end, but I guess that would depend on how much you fed.
        I built a 2′ wide by 20″ high and 8′ long trough and will try that, I can always add to it if needed.

        • It would also depend on how exposed the starting end is. My trough is shorter than yours and the starting end dried out with a couple months neglect, but that was with the lids on. Suppose you kept good covering over your working end of the trough, and left the starting end completely exposed, in good weather it shouldn’t take more than a week or two. Anyway, best of luck and let me know how it turns out. There’s plenty of people spending time and energy separating castings, some of whom might jump at a more passive approach.

  3. Wow! Am I ever glad I found this site! I live in the Bahamas where soil is considered sand with some old leaf mulch mixed in, or some varieties of clay. I just had a friend bring me a couple of hundred red-wigglers and have started a worm bin. Think I will tackle a trough instead now, as I will be reworking my compost area to include a tumbler and cardboard bin. It’s been a struggle here trying to figure out what to use for both the worms and the compost. Will the worms like dried, rinsed seaweed? My amended soil from years of composting includes sand, is that OK for the worms? Also, Casaurina (Australian Pine) needles are plentiful here – green and dried. I use them as mulch, and in my compost, would those be good for worms? Thanks for any help – I have been working on the hit and miss method for years now, and been looking for information like I found here!! So glad I googled “how to use cardboard for compost”

    Sara

    • Hi Sara,
      Hit and miss is my specialty (especially the miss part), and I’m on sandy soil too, so we’re probably a good match to compare notes. Worm farming is definitely a great way to start building soil, as you’re keeping all your nutrients contained until you’re ready to incorporate it. Not sure about the Bahamas but here when it rains all of our nutrients get washed through the sand. My strategy is threefold: One, involve clay into the soil to help bind it together and hold nutrients and water, two, keep a mulch covering over the soil to hold moisture and stimulate microbial activity, and three, grow as many plants and trees on the land as possible to use those nutrients, provide shade and grow food too. Even with these strategies its taken some years for really good soil to develop, so I’ve spent a lot of time choosing plants which don’t need attention, and the rest of my time being patient!
      As for the worm trough, my system currently involves storing kitchen scraps in buckets inoculated with bokashi until I have enough to half-fill a compost tumbler. After the hot phase has finished I transfer the brown compost into the worm trough. About a month later the material is black gold ready to use. Its a more intensive system than necessary but its possible to create a LOT of castings in a short time.
      Also, I’ve successfully put pine needles through this process, though over time they may cause your soil to become acidic, so try a pH test every now and then and make sure its close to neutral.
      Sand is good for worms, as they need some grit in their gut to aid digestion. They might struggle to burrow through compacted sand, so keep that in mind when you’re adding castings and worms to your soil.
      As for seaweed, worms will consume most organic material if its moist. Try adding a little seaweed first, and only add more if you see the first lot breaking down. If there are smells, consider adding the seaweed to your tumbler with other compostables for a faster and perhaps odorless breakdown before adding it to the worm trough.
      Let me know how you get on, and send me a pic of your trough when its done!
      Ps you can also use an old bath tub or fridge on its side as a worm trough!

      • Thanks for the reply! I haven’t got to the trough yet, but I will let you know how it goes. I am thinking my biggest composting problem has been the volume needed for the hot stage – so I have built a smaller but deeper compost bin instead of my 2’tall but 4′ square one. The worms have been happy so far, and seem to like the seaweed.

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