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Composting with Worms: Don’t Make These Five Mistakes

composting mistake banana peelComposting worms speeds up the composting process. New worm bin owners tend to make mistakes. Once you get the hang of vermicomposting, you will love it! Reducing trash, saving the earth, and creating free fertilizer makes worm composting worthwhile. Your household might even adopt the worms as members of the family! Watch out for these five common mistakes.

Mistake #1: Overfeeding

Enthusiastic worm bin owners toss every available scrap into the bin. The worms cannot keep up. The bin starts to smell terrible!

In theory, worms can eat their weight in scraps per day. However, that number might be lower, depending on air temperature and other factors. A fool-proof method is to feed them every 2 to 3 days. Be conservative in the quantity. Soon, you will get a feeling for how much food they can handle. They should start eating one feeding before you add another. An entire feeding should be completely gone in 1 to 2 weeks.

Mistake #2: Wrong Foods

Worms need a healthy diet in small pieces. Whole cabbages and watermelon rind halves will take too long to break down. Processed food, meat scraps, salty snacks, spicy foods, oily sauces, yogurt, pineapple, and bushels of tomatoes can spoil the bin. Most non-food items are also bad ideas.

The ideal diet for composting worms is non-acidic fruit and vegetable scraps. Grains, bread, coffee grounds, tea bags, and pasta are also fair game. Aged grass clippings, hair, and herbivore animal manure are compostable. Add shredded black-ink newsprint in moderation. Torn or shredded brown corrugated cardboard is acceptable. Clean, crushed eggshells add grit and calcium. All items should be small. Larger items should be cut up or run through a food processor. Smaller pieces break down faster. This reduces odor and discourages pests.

Mistake #3: Too Wet or Too Dry Composting Bedding

The over-enthusiastic worm bin owner pours gallons of water on their worms. The negligent owner lets the bin dry out. Too wet, and the bin becomes stinky and the worms might drown. Too dry, and the worms dehydrate, cannot breathe, and can’t tunnel effectively.
The easiest way to check worm bin moisture levels is by picking up a handful. Squeeze it. If water comes out, it’s too wet. Worm bin bedding should have the feeling of a wrung-out sponge.

See our instructions for drying out a wet worm bin. Also find out how to keep the bin moist.

Mistake #4: Forget to Harvest Worm Castings

Avid gardeners eagerly look forward to removing finished compost from their worm bin. Fresh “black gold” is the best organic fertilizer to make plants grow. Gardeners mark the days until the worm castings are ready for harvesting.

However, non-gardeners typically focus on reducing trash and odor. For them, the worm castings are a side-effect. Their worm bin eventually fills up with worm castings. Adding more trays or getting a larger bin puts off the inevitable.

Harvesting finished compost means separating worm castings from the worms. You will leave bedding behind for the worms to live in. Using a screen should only take 30 to 60 minutes. Making mounds takes a day, mostly waiting time. Tray-based composting bins might only take 10 minutes.

Compost can be harvested:

  • at the start and end of the growing season
  • whenever it is getting full
  • as needed, if the worms have been in the bin for at least three months and there are extra worm castings inside

If you have more “black gold” than you need, donate it to a local gardening project or neighbor.

Mistake #5: Too Hot or Too Cold

Just like people, composting worms have an ideal temperature range. The worm bin and bedding help regulate the temperature. When the air temperature is below 54 degrees Fahrenheit, worms slow down. Below freezing, they can die. Above 84 degrees can cook the worms.

Do you live in a climate that has temperature extremes? See our tips for keeping composting worms cool in summer and warm in winter. Bin location is the primary issue. You can mitigate some of the temperature hazards using ice, bin blankets, insulation, relocation, and moisture regulation.

At Uncle Jim’s Worm Farm, we offer expert information about managing your vermicomposting bin. Peruse our blog, check out our product descriptions, and read our Frequently Asked Questions. We are the #1 supplier of composting worms in the USA.

12 comments on “Composting with Worms: Don’t Make These Five Mistakes

  • Peter Kautsky says:

    I used large bins with combination of mulched cardboard and fresh greens. I constantly had the problem of worms wanting to escape. They would be happy for a while and then they would be crawling up the sides of the bin and getting out. I just could not get a median environment to keep them in there.

  • Normally the lower portion of the worm bed is more wet then the top half. Keeping a packing-cardboard sheet on the top and spraying water with a spray bottle can address the problem.

  • John Hartman says:

    my first season using worms for composting was , for me , a huge success. During the cold months I kept them in the basement. THey consumed all the table refuse we gave them. Now i have them in an outdoor raised bed . I am going to let them enrich soil for a few weeks , then move them.
    , rotating the locations in the beds. John

  • I live in a city where temps have been over 100F daily. My worm bin is in my garage but have found by adding frozen water bottles (capped) daily keeps the worms comfortable and happy. The condensation keeps the bedding watered perfectly. They are doing great and are not water drenched from loose ice, another idea for those hot summers.

  • Michael Kordus says:

    Put a LED note light over the top of them . they don’t like light . cover the top with something that they won’t eat . cut to fit a plastic place mat tape together to fit and lite over top.

  • hey peter
    those plastic bins, especially in winter months will tend to sweat on the inside if not properly ventelated, sending panic to the worms they will drown. when i started out, i had 5000 worms trying to escape the bins i thought i had set up right. because it was freezing outsude i had placed bin in guest bathroom. as soon as i added enough ventalatiin to stop condensation from forming, they stopoed. so there is a fine line you will determine, to much air flow drys everything quickly, too little and your redworms will migrate to seeminly better location. 5000+ migrating redworms at xmas while your inlaws are visiting was not a pretty site.
    even though artificial light would have remedied problem temporarily it is not getting to root of problem.

  • I’m using a Worm Factory three tier worm bin and find that a lot of the worms stay in bottom tier the compost. Not all leave to find more food in the next tray up. In fact I regularly find a lot of worms in the bottom pan that drains the “tea” out via the spigot. The next layers up have plenty of worms and food. Why don’t all the worms leave when their kitchen scraps are gone? How can I get the worms to migrate without picking them out one by one?

  • So, even though you’re supposed to put fresh trays on top, I actually put my newest tray on the BOTTOM. I usually only have two trays going. As soon as one tray is mostly “full,” I will start the second tray with a bunch of bedding and some food scraps and put this on the bottom. I will them put the “full” tray on top. This solves several problems. The extra liquid from the full tray seeps down and keeps the bottom tray moist; I never need to water. The top tray acts as a moisture barrier instead of needing to keep a moist newspaper or other covering on top, and it will keep out bugs, etc. Finally, the worms do go DOWN and seem to be quite happy down there. After a little bit of time, the top tray will be “finished,” and I can then harvest the castings (literally scoop them out, no worms, no waiting for worms to move since they are all in the bottom tray). This might not work in all setups, but definitely works in a two-tray setup in the worm factory. Also, extra liquid can still seep out the bottom so there’s no problem with that. I do make sure to keep a good amount of bedding, so there is good aeration for the worms.

  • Barbara Wilsher says:

    DAY 1 AND MY WORMS ARE TRYING TO ESCAPE – They are in full shade, temp outside is between 7 deg and 15 deg Celcius for our winter.

  • I have two 50 gal. bins an a 18 gal. bin. In the winter I use seed heating mats to keep worms an bedding warm. IPOWER carries the mats an thermostat.


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