Step 1. Decide on a suitable place to locate the worm farm – remember, they like cool shade, but you also need to be able to easily access them.
Step 2. Purchase or salvage a suitable sturdy container, eg bathtub or laundry tub. Tip Shops are great for cheap tubs! Also keep an eye out for council collection days in your area or people doing renovations. This one cost me all of $10 from a Tip Shop, but our first one was free from a family member who was renovating.
Step 3. Make a suitable sturdy base for your bathtub or laundry tub. Tubs are quite heavy, especially when full of worms and compost, so make sure its sturdy; you don’t want it collapsing under the weight! We used reclaimed hardwood from a demolition salvage yard that was leftover from constructing our new chook house, but you could use an old metal table frame or whatever other sturdy frame you can get your hands on, even just a few stacked up bessablocks would do, to lift the tub off the ground and allow it to drain (make sure you lift it high enough to put a container underneath if you want to collect the worm ‘juice’!)
Step 4. Put the frame in place and make sure that its level. In this pic, you can see that we’ve put bricks under the feet on the downhill side to lift that end. If you can’t get it perfectly level, it doesn’t matter too much, just make sure that it drains towards the drainage hole (worms can drown if too much liquid collects in the bottom of the tub, and it will stink!).
Step 5. Insert the bathtub or laundry tub into the frame, making sure that it’s stable and won’t tip over.
Step 6. Lining the bottom of the tub is an optional step – we didn’t bother with our first bathtub worm farm, or the one that I had growing up, but I’m trialling a method that I’ve seen others use to see if there’s any difference when it comes to ‘harvest’ time. Whether you choose to line the bottom of the tub or not, you will need to at least put something over the drainage hole so that your worms and castings don’t fall through; much like the bottom of large pots, a scrap of shade cloth or geofabric will do. Once this is done, you can either skip to Step 7 below, or line the bottom of the tub with drainage gravel (we had some left over from replacing the retaining wall out the back) and either a double-layer of geofabric or several layers of shadecloth. If this doesn’t reach all the way up the sides, like ours didn’t, tape the top down so that the castings and food scraps won’t get down the sides.
Step 7. Start putting down the worm castings and food scraps/soaked paper (or if you’re buying a new box of worms, put down whatever bedding material they recommend to get your new worms going).
Step 8. Cover the pile of worms, castings/bedding materials and food with either a worm mat purchased from a garden store, or a hessian bag, or even just a few thick layers of newspaper or cardboard that have been thoroughly soaked in water.
Step 9. Cover the tub with a lid of some kind – we’ve used a sheet of tin that was left over from replacing the fence, but a sheet of corrugated iron or a board would do just as well – and weigh it down with a few bricks or rocks to make sure wind doesn’t blow it off.
You may note that in the second-last pic (Step 8), the bathtub looks very full? This is because, at the time that I took these photos, I was using this tub as a storage vessel to store all of my worms while I emptied out and relined our other bathtub worm farm. Since these photos were taken, I’ve finished the other tub and moved approximately half of that material back into the other tub, so now both bathtubs are approximately half full. When the tubs fill to the level shown in that photo, it’s time to start putting some on your garden.
There are many schools of thought regarding whether you should put the food at one end and castings at the other so that the worms can move between the areas, or whether you should just layer the food on top. The first theory supposedly results in a section that is easier to scoop out and put on the garden without collecting too many worms, but I personally haven’t found much difference, so I do the latter – just layer it on top – because it’s a bit easier when several people have access to the farm (you don’t have to worry about others putting scraps at the ‘wrong’ end). At the end of the day, I don’t think it really matters; the worms are going to find the food wherever you put it, so do whatever works for you.