We often get questions about mold in bokashi buckets. Mold can be a good sign. But it can also be a sign that things are going bad. It really depends on the color of the mold.
White mold in your bokashi bucket
If the mold is white then don’t panic! In fact, white mold is good, and is a sign of a successful bin.
The white mold may be white fluffy mycelium clouds, or smaller specks or strands of white on the surface of the food waste.
The white mold is actually a fungi and shows that the food waste is fermenting rather than putrefying. Fermentation is exactly what you want in your bokashi bucket. So, if you see white mold on your bokashi food waste, you can be confident that everything is going well in your bokashi bucket.
Note: White mold is often considered a sign that some air is getting in to your bokashi bucket. A completely airtight bokashi bucket typically shows no white mold.
Blue or green mold
Black, blue or green mold is a sure sign of a problem with your bokashi pre-compost. These darker colored molds are signs of rotting and putrefaction. These should not be present in bokashi composting.
Often times, dark mold is a sign that your bin has failed. When this happens, dispose of the contents of the bokashi bucket or bury them deeply in the garden. If burying, add a couple of handfuls of bran with the failed pre-compost and leave undisturbed for a few months. The failed pre-compost will eventually assimilate with the soil.
In some cases, if there is only a little blue, green or black mold, you may be able to recover the bucket. Add a couple of handfuls of bokashi bran to the small patch of dark mold, cover and close the lid. Check back in a day or two. The beneficial bokashi microbes may out compete the blue and green molds and get your bokashi bucket back on track.
If you see dark mold on your food waste, make sure to check our troubleshooting guide to help prevent it happening again.
Most commonly problems occur because the bokashi bucket is not completely airtight. Make sure your lid is tightly sealed, the composter is not cracked, and that the spigot is completely closed. Also, make sure that enough bran is being added to the food scraps. We recommend adding about 1 tablespoon of our premium bokashi bran for every 1″ layer of food scraps. More if you are adding hard to compost items such as meat, bones and dairy. Another common problem is using bran that is no longer viable. Bokashi bran needs to be fresh (less than 18 months old) and needs to be stored correctly (How to store bokashi bran). Bran that is old or stored improperly will have far fewer active bokashi microbes and be inefficient for bokashi composting.
No mold in bokashi bucket
Often times, especially with a well sealed airtight bin, you may see no mold at all on your bokashi food waste. That is perfectly normal, and another sign of a healthy bin. The contents should still have the distinctive sweet, pickly smell of bokashi composting.
A successful bokashi bucket does not have to have white mold on it.