We looked at the hard evidence to see if marigolds or their derivatives were effective as a natural mosquito repellent and/or mosquito killer.
Summary of Scientific Research
Green thumb gardeners are often quick to tell new cultivators about the necessity of planting marigolds as an ornamental border. As it turns out, this old rule-of-thumb can actually be backed up by a degree of scientific research. At a biological level, marigolds contain a compound called pyrethrum that is particularly malodorous to a variety of insects, including mosquitos (1).
This compound, along with another natural chemical known as thiophenes, are off-gassed from the plant during its regular biological processes. As a result, mosquitoes and other pests won’t fly anywhere near them. These same chemicals can be found when the plant is broken down and concentrated into an essential oil, allowing a willing user to take “nature’s insecticide” with them when they exit their garden.
The marigolds’ claim to fame with regards to abating mosquitoes has long been known outside the scientific community, making it a reliable option for those already adjusted to planting border plants in their vegetable gardens. However, when compared to other natural mosquito prevention methods, marigolds stand out for their beautiful radiance. This radiance can even be adapted to fit the needs of your living space, with potted marigolds serving just as efficiently as their ground-planted brethren.
While not a sure-hit when it comes to reigning in a mosquito infestation around your home, marigolds are definitely a tried-and-true option that beats resorting the chemical insecticides and DEET-based sprays. To this extent, marigolds are one of the best holistic options for addressing a localized mosquito problem while simultaneously trying to attract bees and butterflies (both of which love to pollinate marigolds).
Marigold Forms and Where to Get it
- Marigold plants – As described, marigolds perform their mosquito-blocking duty best when in their plant form. Luckily, marigolds are not particularly finicky when it comes to growing. Generally, marigolds require full sun and well-drained soil in order to flourish. In order to encourage rapid blooming, you may consider supplementing your top soil with compost, also. Once in full bloom, the marigolds’ full insect-blocking capacity will become fully apparent (2).
- Marigolds can easily be found at your local plant nursery, as well as in seed form online.
- Essential oils – To a lesser degree, marigold oil (often referred to as calendula oil) may be useful for transporting the marigolds’ natural mosquito-blocking capabilities where you need it most. This oil is difficult to make at home, so you best option for obtaining it is through an online source.
- One noteworthy drawback of marigold oil is its photosensitivity. Even at a 0.01% concentration, this oil can react to sunlight and cause irritation for users who apply it dermally (3).
1 – Paul Simon. Science: Could marigolds slay killer mosquitoes?. 17 July 1993.
2 – Matt Suwak. How to Plant and Grow the Glorious Marigold. 23 April 2019
Other Plants & Herbs as Mosquito Repellents
Checkout our analysis of other plants & herbs as natural mosquito repellents: