The wind has died and you are sitting on your boat in a lovely harbor, beverage in hand, watching other boats and the cars on the shore, glad you are no longer part of the rat race when you hear a buzzing sound. Seconds later your feel the sting, you slap, but it’s too late. The darn mosquito has extracted its load of blood and is on its way to breed. In these days of EEE, Zika virus and other mosquito borne diseases, you need to be careful where and how you get bitten.
It doesn’t have to be this way. You can spray the entire deck, yourself and everybody within five yards (4.5m) of the boat with a DEET based bug spray, but sooner or later the bugs will come back (and your spray might be harming you more than the mosquitoes).
So how do you achieve a more permanent solution and keep your boat bug free? One way is to grow your own wall of protection.
Mosquitoes find their target by flying upwind toward the CO2 emitted by people when they breathe. Richly scented plants help to mask the odors that attract mosquitoes. Among these plants you might find:
- Citronella/Lemongrass – a type of lemon scented grass
- Neem – eventually grows into a small tree
- Lemon Scented Geraniums
- Lemon Balm
- Catnip – will attract every cat within five miles, but is even more effective than DEET
- Lavender – also said to help you sleep better (probably because it keeps the bugs away)
- Basil – you can also use in Italian cooking!
Each of these plants can be grown in small pots and kept in the cockpit or below deck when underway.
You will have to buy a small neem tree, but keep in mind that some countries will not let you import plants. If that is so where you are, you can buy neem oil, neem leaf extract, or other neem products (https://neemtreefarms.com). By planting the tree in a small pot, it will stay quite small for a long time. In fact, you could almost bonsai it!
If you cannot import a neem plant, you should buy seeds of any of the above plants. Start them by filling your pots with good quality potting soil. I prefer square four inch pots simply because it is easiest to water them with no spillage. Filling pots tends to make a mess and is best done onshore or on the foredeck where it can be easily washed away. Sprinkle a few seeds in each pot and gently mist the seeds. Cover them with potting soil so that the seeds are about two seed diameters below the surface. Put a piece of plastic wrap over the top of the pot and set it in a place where it will get good light but not strong sunlight. Strong sunlight will heat the surface under the plastic wrap and cook the seeds. The galley sink is an ideal location.
As soon as you see the first seedlings appear in about seven to ten days, remove the plastic wrap. Water or mist the seedlings gently until they are one- to two inch -inches tall, then fertilize with a half strength 10-10-10 fertilizer. (If you can’t find 10-10-10 use any all-round fertilizer such as Miracle-Gro.) Keep your plants moist but not wet. To test how moist they are, stick your finger in the pot. If your finger comes out dry the soil is dry, add water. If your finger comes out with soil sticking to it, the soil is moist and is fine.
As soon as the plants are six to eight inches tall set them around the cockpit, crush one or two leaves to help the smell pervade the area. In theory, the plant odor will mask the carbon dioxide exhaled by humans and you will see no mosquitoes.
Mosquitoes tend to fly upwind toward the scent of their target, my experiments show that the plants should be directly downwind of the people on the boat, however, you might find this differs depending on where you are anchored in relation to the land.