How to make a pet poo worm farm

Posted by Lauren Carter on

If there’s something we didn’t expect pet ownership would make us grateful for, it’s poo. Growing up, there was always lots of it - dog poo, cat poo, picked up before school, tied up in two plastic shopping bins, and flung into the bin for rubbish day. It was taken away so we didn’t need to think about it, or smell it anymore. When we both moved out of home and adopted pets, we continued the same daily tradition of double-bagged poo-flinging, into the stinky bin, and away. 
But then we started living waste-free, and we stopped shopping at supermarkets, so there were no smelly bins, no plastic bags, and no more away. So along came our worm farm, and the piles of poo (just poo), and the re-used brown paper bags we use to pick the poo up on dog walks, land in there. Our worm friends turn all those stinky piles into incredible compost - black gold for our fruit trees. There’s absolutely no smell. And very minimal need for us to do anything other than dig out the amazing compost, tickling the worms out of it as we go, once a year or so. 
This is what’s normal for our kids now. A life where everything is a valuable resource, and we take responsibility for what happens to it, right here, where we are. A life where we’re all part of an interconnected system, even our pets (both dogs and worms). And that’s a lesson that will last our kids their whole lives. 
How to set up a pet poo worm farm*
It is possible to use the waste pets create as a resource in your garden. You can convert their poo to compost in a dedicated worm farm and use the compost to feed ornamental plants and fruit trees (we’d keep it away from veggies and edible herbs so as to avoid any immediate toxins). A worm farm can fit in a garden, a courtyard or on a small balcony, and when working well will produce no smell. Just luscious compost for your garden.  

• A container to keep your worms in. Some ideas include an old bath, Styrofoam boxes, an old bin or barrel, old car tyres, a purpose-built box or a kit from your local nursery.
• A piece of mesh to cover any holes and keep the worms in. Fly screen or shade cloth are ideal.
• Some bedding material. Some ideas include mushroom compost, garden soil, coconut fibre or garden compost, or lightly dampened shredded paper (this is ideal if you’re planning on composting pet poo).
• Worm food. For composting pet poo, don’t feed them other food along with the poo as they’ll just eat the food and ignore the poo (who wouldn’t!). If you want a regular worm farm for your veggie scraps instead of poo, make sure to stay away from citrus and onions. Worms love soft food scraps, hair clippings, crushed egg shells, vacuum cleaner dust, coffee grounds, tea bags, sawdust, soaked cardboard and shredded paper.
• Worms! You’ll need about 1000 worms specifically bred for farming. Look for tiger worms or red or blue wrigglers. Common garden worms are great for soil improvement, but not so effective in a worm farm.
If you’re creating a layered box system to collect worm tea, you’ll need something watertight for your bottom layer. In a bath, you might choose to place a bucket under the drain hole. If you’re using a Styrofoam box, place a watertight one on the bottom. Grab the box or container where your worms will be housed and make sure there are holes in the bottom for drainage. Place it on your watertight, tea-collecting bottom layer, if you have one.
Place mesh over the holes. If you’re using a bath, cover the plughole.
Place your worm bedding material in the box or container.
Add your worms to the middle of the box. If you’re using a bath, place them at one end.
Add some poo for the worms to eat. Use your worm farm when you’re cleaning up your kitty-litter tray or dog poo, in conjunction with carbon matter like shredded paper or recycled paper kitty litter. We collect dog poo in re-used paper bags when we take the dogs for a walk, and this feeds the worms well. Try and keep a good balance between the carbon and nitrogen based matter in your worm farm, as you'd do when making compost. If you’re using a bath, just feed the worms up the end where the worms were placed.
Make sure not to overfeed your worms. Start with a small amount of food and watch to see how quickly they can break it down. Keep an eye on them as you add more.
Don’t feed pet poo to your worms if you’ve recently wormed your pets – worming medication may kill your worm farm! Technically the medication should be benign when it leaves your dog, but if you want to be sure, leave it for a few days before adding it to your worm farm. 
Place a doubled-up sheet of dampened newspaper on top of your worm farm to retain moisture and keep your worms comfy. Then pop a cover on your worm farm – a layer of hessian, or the lid your kit came with will work.
In a few weeks you’ll be able to collect worm tea to feed your garden! Stick to ornamentals and fruit trees if your worms are eating pet poo.
As your worm farm fills up, you’ll be able to place another box or layer on top and fill it with bedding and food for your worms to migrate to. If you’re using a bath, start feeding the worms at the other end of the bath and they’ll move along to their new feeding place.
Harvest the beautifully broken-down compost from the previous nesting/feeding box and use it on the garden. If you have cats, you might like to bury it under some soil and mulch to keep native wildlife safe, while making valuable nutrients available to your plants and out of landfill or waterways. Happy farming!
*This is an excerpt from our book 'A Family Guide to Waste-Free Living', published in 2019 by Plum. You'll still find it at most good bookshops and libraries, or signed copies in our shop
climate solutions permaculture waste-free

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