Unfortunately, commercial mosquito repellents smell terrible and can be rather expensive. In a quest to find a better way, I decided to take a look at the popular claim that certain plants can repel mosquitoes simply by their presence alone.
Yes and no. Many people are filling their patios up with various mosquito-repelling plants, but by themselves, they're more placebic than repelling.
Certain plants contain essential oils that are known to repel mosquitoes and other insects because of their smell, but the plants themselves don't keep bugs away just by being there. They don't naturally release enough oil into the air to actually "repel" bugs, though they can, to a certain degree, mask the smells that mosquitoes are attracted to so they can't find you as easily.
In order for the oils to work as an actual repellent, they must be released into the air by crushing or bruising the leaves and stalks of the plants. But the most effective way to use them is to rub the oils on your skin as a wearable repellent. Just make sure to do a patch test on a small area of skin first, in case you have any sensitivity or allergic reaction to the oils.
Also keep in mind that these essential oils don't last as long as some store-bought repellents. If they're the only protection you're using, be sure to reapply once every hour or two.
Another way to use these oils as a repellent is to burn them. If you have an outdoor fire pit, throw in a few leaves or stalks, or take some with you to the next time you go camping and burn them in your campfire. You can even drop some in the fire when you're out grilling.
Dozens of plants are claimed to have mosquito-repelling qualities, but some of them work better than others. Citronella oil is one of the best for repelling mosquitoes and has been proven to be effective by several research teams. When combined with vanillin, researchers in Thailand found it to be as effective as standard repellents including DEET.
Citronella oil is found in various species of lemongrass (pictured below) and citronella grass.
Lemon balm (pictured below) and lemon thyme are two of the plants with the highest concentration of citronella (38%), so those would make the most effective repellents. Ironically, the so-called "mosquito plant" contains only .09% citronella.
Surprisingly, a study by the American Chemical Society found that nepetalactone, the essential oil found in catnip, is ten times better at repelling mosquitoes than DEET. Other studies have had very mixed results, but overall, catnip oil is considered an effective repellent.
If you want to cover all your bases, just grab a bunch of plants with insect-repellent oils and throw them in a pot together.
If you put them in a window planter, you'll be able to keep your windows open during the day (your lights will still attract the bugs at night). It might not keep them all out, as they plants are just masking your scent, not repelling, but it can greatly reduce the amount that make it in.
Either way, it'll spruce up your deck or patio, keep mosquitoes from zeroing in on your scent, and give you a bunch of options for actual pest repellent while you sit outside (although, you may want to explain to your guests before you start rubbing leaves all over yourself).
If you actually want to extract the oils into a liquid solution, the process can get a bit complicated as you'll need to make a still. To give you a little idea of how it works, check out this guide by Andrew Fletcher.
You can find a few more tips on keeping mosquitoes away in Yumi's guide to DIY repellents. If you have a favorite trick we didn't mention, share with us in the comments.