Readers’ Cures for Mold and Mildew

Because December and January brought unprecedented volumes of rain to the West Coast, the normally unglamorous question, "What’s the best way to battle mold and mildew?" became a hot topic among sailors.

After asking readers for their two cents on the subject, we received a surprising diversity of suggestions — some of which we’d never heard about. Others mirrored the common-sense basics mentioned in our February post: good ventilation (especially in the galley), and a bevy of natural elixirs that are preferable to bleach, which is toxic, stinky, but admittedly effective. There was one recommendation for using a dehumidifier, as well as several condemnations of the famously finicky devices.  

Angela Brantley of the Kelly Petersen 46 Kanaloa reminded us to remove and dry out mattresses regularly: "if you’re a liveaboard, every couple of days, pull up your bed and dry the mattress. We’ve tried all the gadgets but the simplest and cheapest is to just pick up the mattress and let it dry. Yes, it’s work but it does the job.

"Due to all the heavy breathing in staterooms," says Angela, "these areas take on a great deal of moisture. I put many clothing items in two-gallon plastic sealable bags. It makes it much easier to keep clothing dry. It’s not ideal but better than the alternative.”

A few readers reminded everyone to keep their bilges clean and dry, and to be vigilant about wiping down condensation. There were a slew of magic brews that people swear by to best fight mold once it’s taken residence. The most ardent endorsement was for tea tree oil. Bruce Brown of Costa Mesa says it "has been found to treat mold and mildew spores in the air as it evaporates. I put some on board the boat I was sailing on, and the owner’s wife was getting seasick from the scent of the mold. With a four-ounce jar [of tea tree oil], we removed the source of the odor and she has not battled seasickness since!"

Reader Michael Law has his own special brew: "Mix equal parts (50/50) ammonia and hydrogen peroxide. At about a dollar a quart for each, this is an economical and effective cleaner. For heavy jobs, put on some rubber gloves, pour a quart of each in a bucket and wipe away the mold and grime with a thick terry cloth washcloth. Rinsing in a separate bucket of warm water will make your cleaning solution go a lot farther. For smaller jobs, and to keep at the ready, put the mixture in a well labeled spray bottle." 

A few readers swore by citric acid mixed with vinegar: "When we were living aboard and cruising, we fought a constant battle with mold and mildew," recalls Shirlee Smith, formerly of Solstice. "Our favorite cure was citric acid, closely related to the vinegar you mentioned in the article, but without the smell. You’d be surprised how difficult it can be to find distilled white vinegar in the Mediterranean."

Among the more exotic suggestions was the use of charcoal bowls: Doug Rockne wrote: "A method commonly used in Puerto Vallarta (where summer weather is hot and humid) is to put a few ‘charcoal bowls’ around the boat. I cut off the tops of one-gallon water jugs and use the bottoms for a few common BBQ briquettes. No water accumulates, however, I put the jugs in the sinks and over drains just in case. I replace the damp charcoal every month. My 34-ft sailboat stays dry and does not smell."

Brooks Townes offered this old-timey approach: "If you’re a liveaboard, a wood stove is unbeatable for getting her dry and keeping her that way below. The boat, that is. Also keeping the bilges dusty is a big help, liveaboard or not."