How To Make A Bathtub Worm Farm In Eight Easy Steps

Bath-Upturned

Step One:
Get your hands on an old bathtub.
Shouldn’t be too difficult as there seems to be plenty of them for sale. Now that house prices are high many people are choosing to renovate rather than building new. I bought this one on Trade Me for $11.50.

Worm Bath In Frame

Step Two:
Make up a frame to support the bath.
Raising the bath tub means feeding and harvesting the worms and their castings can be done at a comfortable height. I chose to make a timber frame as the cast iron bath was heavy and I needed to feel relaxed that it was safe and not likely to topple over. If you don’t wish to go to this extent concrete blocks or railway sleepers would suffice.

Worm-Farm-Bath-03

Step Three:
Make grate to fit the bottom of the bath.
The purpose of this is to create a free draining environment for the worms and to allow for collection of the liquid fertiliser or “worm tea”.

Chicken Mesh Laid Over Wooden Grid

Step Four:
Place netting over the wooden grate.

I used a staple gun to attach it to the timber so that it remains in the correct position. Small nails or tacks would work equally well.

Tap On Bath Worm Farm

Step Five:
Attach tap to bath waste pipe.
For a few dollars these components can be found in the plumbing department of most hardware stores. Fitting a tap to the base of the bath means that nothing is wasted and the rich black liquid that the worms produce can be used on your garden and house plants.

Weed Mat Used to Line Bath

Step Six:
Line the bath with weed mat.
This matting needs to allow water to flow through it. Some are tightly woven and don’t have good drainage qualities therefore its important to use the right type. To keep the weed mat in place I used 50mm wide sellotape. For the tape to adhere well make sure the surface of the bath is clean and dry.

Transferring Worms Into Bath Worm Farm

Step Seven:
Add bedding.
After shifting bedding and food from some smaller bins I introduced the tiger worms to their “new digs”, approximately 4000 of them.

Bath Worm Farm With Lid

Step Eight:
Cover the worm farm.
Lastly a lid or cover is necessary to keep out the light and to protect the worms from heavy rain and other unwelcome visitors. Worms are photophobic and unlike we humans prefer to be kept in the dark.

At the time of writing this post I hadn’t made any ventilation holes in the lid but will do that within the next few days. Once that has been done my first bathtub worm farm will be complete.

I enjoyed making the worm farm but will use an acrylic bath next time as this one was extremely heavy. That aside I’m sure my worms will relish their new accommodation and hopefully increase their numbers within the next few months.

Perhaps you’ve made a worm farm recently, if so any thoughts, suggestions or comments would be most welcome.

Post Script: Have made some minor changes to the farm as the worms were escaping into the lower area of the bath. With this fine tuning now complete all is working well again … you can check it out here.

42 Responses

  1. lisa
    lisa |

    WOW..very creative.. and an excellent idea!!!

    Will you be leaving this tub out in winter? I had red wigglers last winter and they died in the tub. I had put it in my garage..very depressing to see them dead like that. It took me a while before I had courage to do worm composting again.

  2. kumeunz
    kumeunz |

    Curious to know why you lined it with weed mat?..I just put coir straight into the bottom of my bath..I siliconed a bit of fine mesh over the drain hole,so I can catch the drips,and the worms don’t get out..the wet sloggy base of my can-o-worms gets lots of worms living in it,despite having a ‘drier warmer’ space in the 1st layer tray,so they don’t seem to have to much problem if it gets too wet.I’ve seen a few pix of bath worm farms,after I did mine, and they all have wood or gravel in the base,but I wonder if its really needed,as long as the liquid can drain?.

  3. Jodie
    Jodie |

    Hi there

    I’ve looked at other DIY instructions that have made ventilation holes in the sides of the bath using an angle grinder – is this necessary?

  4. Lynette Hunter
    Lynette Hunter |

    Hi Rodney,
    Here at Carterton Preschool we have attempted your wonderful bath worm farm with help of parents and children – a great learning experience. We have the farm almost ready to go but just wondering as it is a new environment what to put in the base. Perhaps some old compost or peas straw then the scraps to get started.
    We have made a lid which is slightly higher than the bath to alow ventilation but thought we might need carpet, on top of the worms, to ensure darkness what do you suggest?
    We are keeping a photo record if you would like to see them.
    Thanks for the inspiration.
    Lynette

  5. catherine daly
    catherine daly |

    This is a seriously nice design. Now that it’s up and running- how much waste can it handle a week?

  6. catherine daly
    catherine daly |

    Yes, It’s a great place- and perfect for worms- no danger of them ever drying out- all that rain…

  7. Aidan
    Aidan |

    Hello Rodney,
    Came across your post when Googling for info about making a worm farm. Just a question about where to get the worms – where did you get your worms from? I have an old bathtub and thinking of turning it into a worm farm. I do regular composting and my compost bins have loads of worms – do you know would these worms work for a bathtub worm farm? I was thinking just to start the worm farm with some of this wormy compost. Do you think that would work – or would they be the wrong type of worms?
    Thanks,
    Aidan in Nelson

  8. Aidan
    Aidan |

    Thanks Rodney. Can’t say I’ve noticed red and yellow rings but I’ll have to take a closer look. Do they exist normally in the ground? Or would it be more likely that the worms that make their way into a compost bin are just the standard earthworms?

  9. Aidan
    Aidan |

    Ho Rodney,
    How long should it take until it produces some worm juice? I didn’t get anything out in the first week. I added some more scraps and leaves this weekend and watered it. Got a little liquid out but I think it was just a bit of excess water.
    Cheers,
    Aidan

  10. Aidan
    Aidan |

    There has been about half a litre out since but it may be just the excess water. Do you add water to your tubs? if so, how much?

  11. Manish
    Manish |

    Hi Rodney, I’m trying to start a wormfarm at the highschool which I go to. I wanted to know whether or not the wood you are using as the grate is treated? Also how much did everything cost? And one last question, where do you get the worms from? By the way I’m from Auckland.
    Thanks.

  12. Renata
    Renata |

    Hi Rodney. I’m in Hamilton and have been acquiring things for my worm bath. Not set up yet.Have three bin working farms of my own and a Can O’Worms farm. All are pumping. Are going to follow your plan so will get back on that.

    Renata

  13. Renata
    Renata |

    Hi Rodney. Had my bath up and going for two months now. Emptied a kilo or so worms from my Can O’worms. Everything is going well. Just wanted to know how many worms can live comfortably in a bath ? Or how many would you recommend ?

  14. Rob
    Rob |

    Just browsing through and came upon your site, I have a worm farm in an old chest freezer, helps keep the little critters warm in the winter nights.I was interested to read about the use of carpet as a covering, I had been told that all NZ wool carpets made up until the mid 80’s were sprayed with LINDANE at manufacture, any body able to comment?
    Rob

  15. Wendy
    Wendy |

    Hi Rodney,
    I found you via your article in NZ Gardener borrowed from my daughter. I have had worm farms of the Warehouse Variety (square 2 bin) for a couple of years but only once managed to get juice flowing and then the medium and food was really soggy and not nice to use as compost . About Feb last year they all migrated to the bottom bin and drowned so over Easter I set up a new colony hoping to have juice flowing by mid winter. The worm colony has gone but still no juice. I use a mixture of pulp from juicing fruit/veges, kitchen scraps,cardboard and newspaper. The medium isn’t soggy but there is no juice. Do you have any tips please? Last month I removed all the worms by hand, slow job, and flushed water thru which gave me a supply of juice but now I guess it has set back the production again.

  16. Wendy
    Wendy |

    By the way I live in Hamilton, so winter is a bit colder than Auckland – does that slow things up?

  17. Rob
    Rob |

    Hi Rodney.

    Thanks for taking the trouble to explain your method and provide photographs. That is a very neat and tidy worm farm. Clearly it is not an offensive structure in the garden and could be used as a potting bench or similar.
    For those who lack skills or motivation, please don’t be put off. I have successfully used a bath which is just mounted on an old steel frame from a desk. It is hidden inside a shade house for appearance and climatic reasons. I live in Adelaide and it gets ridiculously hot in Summer. The advantage of the bath is that the total volume is so great that it is not subject to wild temperature variation and I can attest to the worms thriving in all seasons.
    I did not even think of the lining method you created. My drain hole is covered by a small piece of shade cloth and I have just loaded all the bedding and food in without liners or drainage media. I am sure your system is more effective but if any lazy types are reading this, you can get away without it.
    I love reading about the experiences and success which others have with their worm farms. I don’t have anything unusual to offer except that I experimented with an old pair of Levis recently. I removed the copper and brass bits and threw them in. They were gone in about three months.

  18. Lyndall
    Lyndall |

    Hi Rodney
    I love your descriptive bath worm farm set-up. The only difference I made was to use blue-metal gravel for drainage instead of the wooden grate.
    Gr8 to read all these bath worm farm experiences.I, like Rob (April 19,2011), love reading and researching worm farm methodology.Rob’s jeans experience proves that Levis are, indeed, made of cotton, even the stitching thread must have been cotton ‘cos the worms wouldn’t have turned up their prostomium for polyester!! Here in Perth, like Adelaide, Summers are extreme. My bath farm is in the garage and I’m able to maintain temps in the farm itself at around 23-27degs by leaving the lid off during the day and await the, hopefully,cooling late arvo southerly breeze. I feed mainly horse manure to the bath worms as I have a readily available source from stables nearby. I collect this and dredge it for around 3-4weeks before feeding to the worms – they are into it within a few hours – kids in a lolly shop couldn’t be happier!! I top the manure with a large qty of newspaper pulp (approx 6 newspapers which I’ve soaked in water over 5 days then shredded). This pulp retains moisture in the farm over a long period.I harvest half the farm’s worms from their castings every 3 months and replenish their bedding using my home-grown aged compost.

  19. Crystal
    Crystal |

    Rodney,
    I loved your idea and it so happened the neighbor had two tubs he was getting rid of. We so graciously took them off his hands. lol.

    My question is this: I live in the south (aka land of many bugs). The tubs they are in now have ventilation holes and it seems they always get an infestation of flies or something no matter how deep I bury the food or how many layers of cardboard I wet and lay on top. I would like to cover the worms with a wood lid and then cut a couple inch square in it and put a layer of astroturf there. Do you think that would keep the bugs out but still let enough air in? Thanks

  20. Crystal
    Crystal |

    Rodney, thank you so much for your response. A fine mesh is a good Idea. The astroturf was an idea I thought of to use as an alternative to the carpet. Through my reading on worm bins I read that mold competes with the worms for food and that mold is a sign of the environment being too damp and hot. I thought the carpet might mold in the worm bin. I’m not sure if the information is accurate or not. Evidently it hasn’t posed a problem for your bins yet, so I imagine it wouldn’t be an issue?
    Again, thanks for your reply, the bins are coming together quite nicely. Is there a place to send pictures when they are finished?

  21. Rebecca
    Rebecca |

    Hi Rodney,
    We are first time worm farmers and are using an old milk trough so similar to the bath. Sorry if I sound a bit daft but how do you get the worm castings? We have followed your instructions. And have a tap for the juice. Thanks for your help.

  22. John
    John |

    So this is the first time you have harvested the castings in two years? I have a rubbish bin that has been converted into a worm farm by CERES and was wondering how I harvest the castings as well. Do you just take all the castings out and pick out the worms?

  23. Susannah
    Susannah |

    Have progressed from chickens to worm farm and again I’m delighted with the prospect of making a worm farm too. Your info and advice for all the questions is fantastic and makes me realise that there are lots of others out there who need to ask “daft” questions just to be reassured they’re on the right path.

  24. Abraham
    Abraham |

    If your worms died during the winter I recommend building a “cold frame” around your wormery or a little greenhouse with pvc pipes and plastic. Its extremely cheap to build the pvc greenhouse.

  25. Bill
    Bill |

    Hi I have used an old laundry double deep sink for my farm it had a double drain with a single drain for a trap, I put a bucket under it, it was already on legs the sink is made of plastic I built a wood top for it, filled it with soil and leaves, and use kitchen scrapes added crawlers, in about 2 weeks, I have about a gallon of tea thus far, I thought of pouring it into my rain barrel for use in my garden in spring and sending it thru the PVC irrigation lines over my garden

  26. stefano
    stefano |

    I have a tub as well I use for fishing worms , Funny . I use to purchase my worms, Only to learn this past wet season that if you lay any type wood stump or ply wood in your dirt area of the yard, that in a few weeks you have nothing but worms that come up to eat . I now get worms that I pull up from my yard and put in my tub for storage . When I fish i get the so called “Tub Worms” and replace them every so week with the worms pulled up from my yard
    I believe the secret is to keep the dirt area wet or moist. I`ll water the area every 3 days or so and check every Once a week for worms. I also put grass cuttings for food for them to eat when they do come up. I feed the worms in the tub a mix of corn meal and oat meal. That fattens them up!.. coffee grounds work too

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