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Can I Compost That? (Worm Farm Edition)

You’ve likely been in a situation where you’ve asked yourself “can I compost that?” and if the answer is “I don’t know” whilst shrugging your shoulders – here is a quick mental path you can go down to take make this decision on “Can I Compost that?” 


If you have a worm farm, be it above ground or below ground, this process is known as a cold composting method meaning that composting worms and microbes do the heavy lifting break down organic material. They do this by grinding very small food particles in their gizzard with other small gritty particles, like sand and dirt. The organic material and any other bacteria is processed in their gut which then produce castings – which is their poop! Another key bit of information is that worms are omnivores; they primarily feed on decaying organic and animal material. Now that we have the basic anatomy of a worm sorted and their preference in dietary nutrients, let’s talk about different foods we can add in the context of Green light, Orange light and Red light.


Green Light foods – all you can eat Buffet!

  • Uncooked household organic kitchen scraps 
    • Veggie and fruit peels, Meal prep scraps   
  • Fruit skins and pits: avocado and all stone fruits 
  • Dried fruit and nuts
  • Citrus – Chop up into small pieces 
  • Egg shells, coffee grounds, tea bags   
  • Juicing pulp (they love this)
  • Cardboard boxes, shredded paper 
  • Toilet rolls
  • Wood shaving
  • Crunchy Autumn leaves 

Green Light foods are easily broken down in the worm farm by both worms and microbes – they also hold quite a bit of water so as they break down reducing in volume while releasing the water to the worm farm. 


Orange Light foods – maybe add once a week in small handful amounts

  • Leftover salad from dinner: try separating out dairy, meat from the salad before adding to your worm farm 
  • Left over mash from dinner: Avoid if large amounts of cheese and dairy have been added
  • Bread: the yeast in bread provides a lovely growing bed for fungi, if you are going to add make sure to tear into small pieces and mix in well with either a handful of dirt or shredded paper. 
  • Hot chips/ wedges: Chop into small pieces
  • Steamed veggies: Drain any butter or oil before adding 
  • Left over smoothies: preferably with non-dairy milks or additives 
  • Left over home cooked breads and slices: preferable with non-dairy milks or additives 
  • Cooked rice with no dairy or butter additives in very small amounts, mixed in well. 


Red Light foods – Meat and heavy dairy 

Rather than listing these foods, let’s talk about why we suggest not adding these foods – generally speaking, meat needs to be kept in the fridge so pathogens don’t grow, so taking that same logic and applying it to a worm farm – regardless of chopping meat into small pieces the worms and microbes would not be able to digest quick enough, coupled with non-refrigerated temperatures you can see how quickly bacteria could grow. The worms would eventually break down these pathogens, however in the interest of keeping worm farming easy – we suggest not adding this to yours. 


Remember to always aerate your worm farm, mix until old and new scraps have combined.


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