This post was most recently updated on March 26th, 2020
This post is written by Melissa Keyser, a professional organizer and ecological landscape designer dedicated to helping people simplify, live sustainably, and love their home.
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Growing marigolds in the vegetable garden is an easy and colorful way to repel pests without chemicals. This may sound like an old wive’s tale or a method of gardening from a folk story, but this is an example of companion planting.
Understanding Companion Planting
Companion planting is a simple way that can give you a more productive and healthy garden.
It’s a simple concept, but one that’s often overlooked in favor of a more “neat and orderly” garden and plots of just one plant.
Just like how people have friends who support them and keep each other happy and healthy, plants have similar friends. And for gardeners who recognize those relations, it’s common to find marigolds in the garden because it’s a very popular friend!
Companion planting is one of the oldest gardening traditions, with records found from ancient Rome detailing the method. There are many ways that a companion plant can help another- corn creating shade for a more delicate lettuce, for example. Or, they can attract beneficial insects to prey on a pest plaguing the other veggies in the bed.
They can prevent pest problems in the first place by producing odors that keep the bad bugs at bay.
Benefits of growing marigolds in the vegetable garden
There are many reasons to grow marigolds in the garden, and companion planting with marigolds might just help solve many of your garden problems! Here are some of the ways they can benefit your garden:
1. Controlling Nematodes:
Not to be confused with beneficial nematodes, if you have a type of microscopic and parasitic long, thin worm that lives in the soil and destroys the roots of your vegetable plants, marigold companion planting might be the secret to a thriving garden.
There is strong evidence that both types of marigolds (Tagetes patula and T. erecta) produce a secretion that discourages the nematodes. A study done by Connecticut Agricultural Experiment Station showed that when a field infested with nematodes was planted solidly with marigolds and then plowed over, it provided control for two to three years. This gave better results than any other method experimented with.
To take advantage of this natural repellent, plant as many marigolds as you can in the nematode infested area. They should be planted in a block, not intermixed with other crops.
It will not work for nematode control if only scattered about in the garden amongst the other plants. When they start to flower, chop them and turn under the entire block of plants into the soil- much like you would a cover crop.
2. Trap crop for aphids
Marigolds can also act as a trap crop for aphids. Trap crops work by luring away the aphids from the desired veggie and instead go for the trap crop. Instead of the aphids covering and sucking the plant juices from your prized peas, cabbages, marigolds can lure the aphids away.
3. Repelling Mexican bean Beetles
Marigolds in the garden can also help repel Mexican Bean Beetles. These oval tan beetles, and their larva, chew through bean leaves, even to the death of the bean plant! These pests are the most harmful in large, bean-only garden plots. Instead, marigold companion plantings thought-out the bean section can help keep them away.
4. Repelling Flea Beetles
Just like how marigolds can repel bean beetles, they have also been known to repel flea beetles from eggplant. These tiny black beetles that jump around and make the leaves of your eggplants look like they were shot full of tiny bullets.
It’s thought that the strong scent of marigolds acts as a natural repellent, but it’s also possible that they work because they confuse the beetles and they are not able to locate their plant victims.
5. Attract beneficial insects
The smell of marigolds is quite strong, and not necessarily one that you’d want to bring into the home for a bouquet.
A member of the Asteraceae family, these bright flowers are an important food source for beneficial insects like hover-flies and parasitic wasps. When not eating the bad bugs, hover-flies also need pollen and nectar. Having marigolds, and other flowers, in the garden ensure the beneficial insects stick around and lay their eggs.
Growing Marigolds in the Vegetable Garden
Marigolds are a simple, unfussy annual that are easy to grow. They bloom in the summer, and can either be direct sown after any danger of frost has past. Or, they can be started inside four to six weeks before your average last frost date. They are also a common and inexpensive annual bedding plant available at plant shops and nurseries
Pinching growing tips will create bushier plants, and deadheading frequently will keep them in bloom.
There are varieties of Marigolds that come in single or double flowers and range from yellow, orange, red, and rust. The single-flowered types, like “Lemon Gem”, are said to be especially attractive to beneficial insects.
So when you are planning your next garden or shopping at the local garden center, consider growing marigolds in the vegetable! Your veggies and the beneficial insects will thank you!
If you are new to gardening you should check out our beginner gardening course – we hold your hand for a whole year, telling you what to plant and when, as well as educating you along the way. Find out more here.