Indoor Composting Explained – Worm & Bokashi Tips!

Colder temperatures can make that walk out to your compost pile seem LOOOOOOONG, so we wanted to share two pretty awesome ways to take your composting game indoors for the winter. 

Allow us to introduce you to: Worm Composting & Bokashi Composting!

Each method requires different equipment, space, and organic material to work well but both have the benefit of creating incredibly nutrient rich compost with little to no involvement outside. 

First up – Worm Composting or Vermicomposting

Vermicomposting is a fancy word for earthworms doing the work. In a nutshell (pun intended), the worms eat your food scraps, digest them, and leave castings behind.  Their castings are actually humus, which is nutritious compost filled with microorganisms that plants love. They literally eat it up! 

Note: worm castings, vermicompost, humus = worm poop. We’ll use the fancier terms to keep it classy but yes, that is what we’re discussing here. 

Red wiggler worms thrive best in high moisture, room temperature environments (Think basement). 

They are hermaphrodites, meaning they have both male and female parts, but they do require two to mate and will reproduce quickly in an ideal environment. They hang out and feed on the surface rather than digging deep down into the soil. For this reason, you want to avoid opening the lid too often as they do not like light, and will scurry away to avoid it. .

Worms need moisture, but can be sensitive to the amount. You want to ensure that there is a medium level of moisture in your bin at all times, like a wrung out sponge which is similar to traditional composting. If your bin dries out, simply use a spray bottle with water, but usually food scraps hold enough water to keep the worms happy. . 

To start, you can look into ready made bins, but prices vary so it will depend on how turn key you’d like to make the process.  Making your own at home can save money and also get your creative DIY gears turning, so don’t be shy to look around and see what you can use. 

If you’re making your own, you’ll need something that can have a few layers. You will have two levels of bins with bedding and a third level at the bottom. Here’s a quick breakdown of the process:

  1. Worms eat through the first container of bedding and food scraps and leave behind humus. 
  2. You then add bedding and food scraps to the next level and the worms will be attracted to and move into that level, leaving the original level open for you to harvest the compost.
  3. Continue switching those two levels back and forth. 

The third level at the bottom catches any moisture from the top two levels, which is called “Vermicompost tea” and is another fantastic addition to your fertilizer arsenal.   

Keep a close eye on the bins. After about 3 months, you should have a considerable amount of vermicompost or worm castings to add to your garden. Be sure to mix it up every now and then.. This ensures that there is an even layer of moisture throughout the whole bin rather than dry pockets and super wet pockets.

You will also want to empty the “vermicompost tea” fairly often, as it may create a smell.

When harvesting your castings, you may need to sort it manually and separate out the worms. 

Food Scraps that are Ideal for Worm Composting:

You want to focus on foods that are soft, moist and little to no acidity as worms definitely don’t like acidic foods. You also do not want to put any animal food products because they will take a more significant amount of time to be digested and can introduce unwanted bacteria while creating bad smells. Any food scraps you put into your bin should be chopped up into smaller pieces, to aid in the breakdown. You also want to give a wide variety of food scraps, not just one type of food all the time. 

  • Fruit and vegetable peels
  • Melon rinds
  • Coffee grounds
  • Tea bags
  • Bread and plain pasta
  • Lettuces and greens
  • Eggshells – one exception to the no animal product rule, as crushed eggshells add grit and also help increase the pH balance of the bin. 

Remember, your worms are living beings, so be sure what they are feeding is contributing to their good health. 

Food Scraps to Avoid in Worm Composting:

  • Citrus – oranges, lemons, limes, grapefruits
  • Pineapples
  • Tomatoes
  • Animal products- bones, fats, oils, any types of dairy
  • Salty foods
  • Onions 
  • Potatoes, potato peels
  • Any toxic materials such as –
    • sawdust from pressure treated wood 

Not up for some new pets this winter? Never fear! Because our next option does not include running a worm hotel (although we think those red wigglers are pretty cute).

Next Up – Bokashi Composting

Bokashi Composting is another method of home composting that originated in Japan. The word Bokashi literally translates to “fermented organic matter”, and that’s pretty much exactly what you’re doing. Creating compost through a fermentation process. 

Usually in composting systems, you want air flow so materials can break down via aerobic composting. With the Bokashi method, you are eliminating air flow and the materials are undergoing a process known as anaerobic composting.

The cool thing about the Bokashi method is that you can compost meat and dairy scraps as well as all your vegetable scraps, which is something that can be tricky in backyard composting systems as well. 

One major important player in this game is Effective Microorganisms or EM. This can otherwise be known as Bokashi bran. It comes as dry flakes. You may see a liquid version of EM, but for the Bokashi method, you want the flakes. 

There are a couple different ways to make this bran at home, but it is suggested that you just purchase the bran, because it is a time consuming and finicky process. If you choose to make your bran at home, there are a myriad of recipes and methods online.

You can use two 5 gallon buckets to get rolling with Bokashi. All you’ll need is a drill for some holes and you’ll be good to go. Here’s an overview of the process:


  • Take one bucket, and drill holes at the bottom
  • Place inside the other bucket
  • Sprinkle a layer of Effective Microorganisms along the bottom
  • Then add a layer about two inches thick of food scraps
  • Use the masher tool to push all the food scraps down, leaving NO room for pockets of air – we don’t want oxygen in Bokashi 
  • Then cover with a paper plate or aluminum plate (formed to fit the bucket) – this helps reduce the air hitting the food scraps
  • Place the lid on tightly, wait.
  • Continue adding layers as you go, like lasagna: sprinkle of EM, two inch layer thick food scraps, and mash.
  • Fill the bucket over the course of a couple weeks (depending on how much food scraps you are generating) 
  • Be sure to empty out the liquid that drains out into the bottom bucket – this is called “Bokashi Tea”
    • Use Bokashi Tea when watering your plants! It must be diluted. Typically one teaspoon per gallon of water
  • Once the bucket is full, leave it alone for two weeks. The lack of oxygen will aid in the breakdown and fermentation process. 
  • After two weeks, take the bucket outside and dig a hole about 8-10 inches deep, dump the bucket, and cover that with soil.
  • Wait another two weeks, and then plant on top!

Be sure to keep an eye out for mold.White mold is okay, and actually a good sign that the fermentation process is happening and healthy. On the other hand, green, blue, or black mold is a sign of rot and a failed bin. But you can fail up in Bokashi! Just bury it deeper in the garden, and sprinkle some EM bran and leave it be for a couple weeks or months. It will eventually become part of the garden soil. 

Pretty amazing how many different, simple ways there are to recycle your food waste.

We’ll be sharing some of our own indoor composting projects shortly but in the meantime, COMPOST ON!!!





If you live on the Philly Main Line, take advantage of our composting service!

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