A fleet of small black gnats recently took up residence in the composting chamber of my houseboat’s newly installed Nature’s Head. I'm ignorant of gnats' life cycles and lifestyles so only guessing that the original pair may have entered the composting chamber via the passive ventilator hose.
They quickly set up housekeeping and invited family and friends.
I consulted an online forum of sailors for their expertise on such infestations.
One expert suggested gnats show up if the composting chamber is too damp. The chamber is supposed to be damp to grow the aerobic bacteria that begins the composting process but the moisture level must be titrated. Too much moisture encourages the stinky kind of anaerobic bacteria.
My head doesn’t stink, or even smell, but has nevertheless provided a fecund environment to gnats.
Lovely bunch of coconuts
Coir, pronounced “coy-er”, is a natural material made from coconut husks. For the purposes of heads, coir comes in dry brick form -- one brick per session -- that must be dampened and crumbled before installing.One coco-composter shared his experience:
While using Cocopeat [coir bricks] I had no bugs. Life was good. My compost wasn't excessively moist, a bit on the drier side. (If it gets too wet, it is hard to turn...and it looks gross, too.)
One very rainy day I left a vent open on deck and water infiltrated the solids tank. I removed some of the mess and added Sorghum peat. My head was never the same. I ended up with a gnat infestation. I tried dematiaceous earth, no luck. I ended up dumping it all* – not too gross – cleaning well, and starting over.
If this happens to you, keep in mind, gnat eggs are sticky and laid in crevices. Simply emptying the tank and restarting doesn’t help. The eggs must be completely removed. My Nature's Head has a lip all the way around and eggs were way up in there. I used a powerful spray nozzle to break them loose. It took a long time because of their location. Also had to clean out the vent and fan screens as they were in there, too.
Bring on the gnats
After a week reading about gnats and heads, I returned to my houseboat ready to rumble.I spread large garbage bags over the composting chamber, flipped it to pour the composted material into the bag, washed and wiped the chamber interior, then set it in the hot sun (a formidable insecticide). I repeated that process with the upper chamber.
After several hours in the sun, I reassembled the head, sprinkled crumbled coir into it, and assembled the unit. Now I wait to see if this treatment worked.
* US Coast Guard considers a composting toilet a Type III marine sanitation device that can be used anywhere in US waters. But, do not dump "compost" into the water, and never anywhere within the 3 mile territorial limit.
