I tried the whole cedar and lavender routine. Rings, blocks, sachets, oil. It smells great when you open the closet. It is not a silver bullet.
What the evidence says
- Cedar has limits. UC IPM notes aromatic eastern red cedar oil can kill small larvae, but not large ones, and the effect drops as the wood ages. A tight container often matters more than the wood itself. The University of Kentucky adds that cedar closets are seldom effective because vapor levels are too low in typical, unsealed spaces.
- Lavender and similar sachets are adult repellents at best. English Heritage says these can help in enclosed spaces and must be replaced often. They do not touch larvae already inside textiles. That matches my experience. (English Heritage)
How I use cedar now
- I focus on sealed volume, not "cedar everywhere." Garment bags and lidded bins concentrate the scent.
- I refresh blocks by sanding lightly and I add a little cedar oil to the block surface, then let it dry before it goes in with clothes. That perks up the smell.
- I treat cedar as a deterrent layer after I have already done hot wash, dry cleaning, or freezing. It is not my front line.
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What did not earn its keep
- Lavender sachets in an open closet. I tried many and could not see a difference in trap counts or damage. In sealed bags they smelled nice and might help, but I could not prove impact.
Where this leaves me Cedar and lavender make a treated, sealed container a little less inviting for adults. They do not solve an active problem. If you have visible damage or trap captures, go straight to laundering, dry cleaning, or freezing, then seal.