Plum Bloom on Beeswax




We received a great question and beautiful photos from Rachelle (below) and Valerie (above). The comb in Rachelle’s hive has dark wax with a thin layer of white on top. She was wondering what the white layer is and if it is cause for concern.




Answer: This white coating is called “Plum Bloom.” The bloom is a light powdery substance that comes from within the wax. It is a normal characteristic of beeswax and beekeepers don’t need to do anything about it.

Wax bloom happens with changes in temperature. When the weather warms up again, it usually vanishes.




We often see this bloom on our beeswax candles. Only candles made from 100% beeswax will bloom. When we get out our beeswax candle Nativity every year in December, we like to buff off some of the bloom with a cloth, which exposes the raised surfaces of the wax. We leave some of it in the cracks because it brings out the details, like in this baby Jesus pictured.





Many people see plum bloom and wonder if it is mold. It is not, but mold CAN grow in hives. We see mold most often around clusters of dead bees on the comb in the spring. We rarely see mold in strong colonies, because worker bees will clean out dead bees before mold can grow.


Photo credit goes to
Photo credit goes to

If you do see mold in your hive, you will need to remove the it before starting fresh with new bees. In Middle Bar Frames, cut out the moldy comb with a knife, just larger than the moldy area. Bees will repair damaged comb as they are working in the hive.

If using a frame with foundation, use your hive tool to scrape the wax down to the foundation around the moldy area, removing the moldy parts, and use the frame again.


2 responses to “Plum Bloom on Beeswax”

  1. I have black mold inside one of my hives. But it’s on the wood, not on the comb. I’m hesitant to harvest any honey or wax in case there’s a risk of consuming something with black mold spores in it. But the bees never bothered cleaning it up. Any suggestions?

    1. thehoneycompany Avatar

      All kinds of mold occur in a bees’ natural nesting site. Like, a hollow log would be filled with all kinds of mold and bacteria. Honey is good at killing bacteria as it is acidic and hygroscopic (it sucks water from its surroundings, including from bacteria). If it were me, I would feel safe eating it.

      If you are still worried about it, you could scrape most of the mold from the frame with your hive tool. But your goal in cleaning up frames isn’t to sterilize the hive. Whether benign or beneficial, all the microflora fill a niche in the ecology of the hive. The only risky bacteria are from American Foulbrood, as it could re-infect bees with the disease. The risk would be for the bees and not for human consumption of the honey (after humans are >1 year old).

      If there were mice in the hive, I would avoid eating the honey near the damaged comb. Mouse germs are not a risk to the bees.

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