14 Plants Which Repel Insect Pests

The flowers make a relaxing tea, and also emit chemicals, pyrethrins, which act as an effective insect repellant. This actually affects all insects, and when concentrated, it can even inhibit female mosquitos from biting. Unfortunately, “all insects” includes pollinators, so don’t expect many fruit or seeds nearby.

They also repel non-garden insect pests, inluding ticks, lice, fleas, and silverfish. Grown as houseplants, chrysanthemums can also help clean the air.

A lot of old school gardeners will tell you to plant Marigolds everywhere in your garden, because they can act as companions to all kinds of plants. They both attract beneficial insects like pollinators, and repel unwanted insects – including root-knot nematodes, beet leaf hoppers, cucumber beetle, squash bug, onion fly, and cabbage root fly.

French marigolds emit a pesticidal chemical from their roots, which is strong enough to stay in the soil for some time after the plant is gone. Mexican marigolds do the same, but are powerful enough to even affect some more delicate plants, so they should be used sparingly!

Onions not only taste great, but they’re excellent at repelling pests. Among others, they keep away aphids, Japanese beetles, potato beetles, carrot flies, and even rabbits.

Garlic is even more effective, repelling aphids, slugs and snails, tree borers, cabbage maggots, and ants.

Growing peppermint or spearmint (and probably other types of mint too) will keep away aphids, onion fly, cabbage root fly, and ants. Be careful though, as mint grows prolifically and will happily take over your garden. Keep it in a pot. If you have pets, spearmint also repels fleas. Cats are quite fond of it too.

I love fresh chives. Several insects do not, including mites, aphids, cabbage worms, carrot fly, and nematodes.

Corriander (Cilantro)
A certain percentage of people have a genetic trait which makes the taste of corriander leaves unpleasant and overpowering to them. But even if you’re one of those people, it’s a helpful plant to grow, because it keeps away aphids, whitefly, and potato beetle. It’s also one of the few plants that can repel spider mites.

I mentioned above that onions repel carrot fly. Conveniently enough, carrots repel onion fly.

An extremely useful herb to plant around leafy greens, fennel repels aphids as well as slugs and snails.

These plants are very good at defending themselves. They’ll repel some pests, but they’re also good at attracting predatory wasps which will take care of insects pests. Mustard plants also have a more extreme method of self defence – if anything lays eggs on the plant, it’ll sacrifice part of the leaf those eggs are laid on, so the eggs fall off.

These are very pretty flowers, which can keep a load of insects at bay. In particular, they repel aphids, whitefly, squash bug, carrot fly, and numerous types of beetle. They also repel most major cabbage pests.

A mild flavoured herb, which can repel spider mites, as well as aphids, squash bugs, and cabbage looper.

A tasty salad herb which goes nicely with sundried tomatoes, and repels a few different insects, including mosquitos. Unfortunately, aphids love it, so you should choose a good companion plant for it.

You can brew a nice relaxing tea from catnip. It can also repel aphids, squash bugs, weevils, and various beetles including cockroaches. Of course, it’ll also attract cats. Which may or may not be a bad thing, depending on whether you like cats.

Tastes good in cooking, smells good as incense, and keeps away cabbage fies, carrot fly, black flea beetle, cabbage looper, and cabbage maggot. Grow it near beans to protect them from various parasites.



A hori-hori is a Japanese multi-purpose gardening tool. They were originally invented by foragers  to carefully excavate sansai (mountain vegetables).

Also known as a “weeding knife” or a “Japanese gardening knife”, it has a sharp blade for cutting through tough roots or stems. The blade is also concave to act as a trowel, has a serrated edge to act as a saw, and often has markings to be used as measurements (for example, to measure how deeply bulbs are being planted).

Gardening knives can have sizes anywhere from 4.5 cm to over 17 cm. A hori-hori can be a very useful addition to any serious gardener’s toolkit though, as always, care should be taken with sharp gardening tools.



And of course, you can scale this up with multiple trays and fish tanks, you can connect them in series so one set of fish provides for another bed of plants down the line, and you can also scale up the size of the fish tanks and the plant containers. The only thing I don’t see addressed in the diagram is the aeration of the water for the fish tanks to make sure they get enough oxygen, but adding one or two aquarium pumps wouldn’t pose too much of a technical or financial burden. It might also be possible to use the agitation of water by the addition of other water to a tank as a means of oxygenation, especially if the tank and the input / output system was big enough.



I’m very glad people raise these points. Obviously, this is a concern when you’re recycling things to use in your garden, so I looked into it a little…


Tyres, like many types of rubber, are treated with various chemicals during manufacture. The ones of most concern are plasticisers. These tend to mostly leach out in the first year or so – they’re what gives rubber that sharp, bitter smell when it’s still new.

Some links:

Unfortunately, my only conclusion is that, without any proper research, it looks inconclusive. It seems like tyres should be safe enough to use, but I can’t say for certain. Best not to use them for growing food, I’d say. Better safe than sorry.

They’ll still work nicely for growing flowers and non-edible plants, though.

Wooden Pallets

Yes, these can be contaminated, so be careful. The biggest concern is if they’ve been treated with any chemicals – the worst of these chemicals are, to my knowledge, banned in the EU and no longer used in the US. Even so, here are some helpful links:

To summarise, wooden pallets for international use have markings to show if they’ve been treated. The best are marked DB and are untreated. Markings of EPAL, KD, or HY are also fine. These are heat treatments which have no lasting effects.

Ones to avoid are any which are painted in bright colours, or marked EUR (treated but non-specific – so it could be anything). If you find one marked MB, avoid it because that stuff is nasty.

If it has no markings, then it wasn’t intended for international use. These are mostly left untreated, but there’s no way to be sure, so use with caution.

I haven’t found so much about the collars, but I’m assuming the same rules apply.

I hope some of you find this useful!

@coccinelf @vaguearies


This greenhouse is using purple LED lights to save energy while growing plants. The idea is that the lights provide only the most useful wavelengths of light that the plants need to grow – so no electricity is wasted on generating light which won’t be used.

(image via)



Oh, I really like that idea. So easy to do. And it’d be great for all kinds of root vegetables! Carrots, parsnips, cassava, taro, burdock. Actually, especially burdock. Very healthy but a real pain to try and dig up.

As a random aside, BTW, sweet potatoes are a great plant to grow because every last part of the plant is edible! The leaves apparently make quite a good spinach substitute. Sweet potatoes can contain a lot of oxalate though, so be sure to cook them thoroughly. Adding some lemon juice helps too.