Do Marigolds Deter Aphids?

Aphids are attracted to beans, melons, roses, and potatoes among other flowers and vegetables. These insects drink the sap of plants, essentially stunting their growth.

Planting marigolds is one of the few natural methods of keeping aphids away. These insects have certain flowers they hate such as marigolds and catnip.

Aphids are considerably deterred by marigolds. The flowers need to be planted 2 months ahead of plants that aphids like for them to root and to efficiently keep the insects away. Multiple marigolds are needed to keep aphids away in gardens.

Marigolds have a specific odor that aphids hate. Furthermore, they release a toxin from their roots that aphids and other invasive species such as nematodes hate.

As a result, there’s no reason not to plant marigolds in your garden that has aphid problems. The only question is how to plant marigolds to keep aphids away.

3 reasons why marigolds deter aphids

Marigolds aren’t magical plants that keep aphids away. They are flowers that deter insects through odor and toxins.

Most importantly, you need to plant marigolds correctly, space them out accordingly, and consider their limits when it comes to deterring aphids.

Do Marigolds Deter Aphids?

1 – Strong repelling odor

A strong odor is what repels aphids when it comes to marigolds. This odor is what aphids don’t like most about the flowers. They do everything they can to escape and to move along to a different area.

You can still see aphids on marigolds if they find there’s a good chance to find food nearby, but these cases are rare.

The strong odor of marigolds isn’t a standard flower fragrance as not all marigold types are scented. Only scented marigolds turn aphids away and these species aren’t very common in North America. Many are imported species from Europe.

2 – Alpha-terthienyl toxin

There’s no scientific evidence to support the idea that aphids are deterred by marigolds. This is just the realization of gardeners and farmers looking for natural methods to keep pests away.

However, there’s research that shows marigolds release toxins from their roots, especially in the second year of growth. These toxins that contain Alpha-terthienyl are proven to keep certain pests away.

Among others, these toxins are known to keep nematodes away. Many believe these toxins to be the organic compounds that also keep aphids away.

Studies also show that simply placing marigolds in a pot next to plants affected by aphids won’t make them go away. Marigolds need to be planted before the other invaded plants or trees to be efficient.

3 – Attracting lady bugs

Marigolds come in different colors. They are used as decoration in gardens. Yellow and orange marigolds keep aphids away the most. But these colorful flowers also attract lady bugs.

ladybug eating aphids

This is important as lady bugs extensively eat aphids. Friendly-looking lady bugs are known to almost exclusively feed on aphids which makes them a very efficient method of controlling aphid spread in gardens and even on crops.

Lady bugs are known, predators. They locate aphids and aphid eggs they consume to the point of extension.

How to plant marigolds to keep aphids away

Even the right marigolds might not fully deter aphids. There’s a clear indication to show that planting the flowers in the right way is needed to deter aphids.

Plant marigolds at least 2 months ahead of other plants

One of the biggest problems with marigolds is they need to be planted in advance for them to root and start releasing toxins that deter pests and insects.

Marigolds take at least 2 months to start growing roots properly. Furthermore, some research suggests planting marigolds at least 1 year before you start investing in a garden for the flowers to fully conform to the environment.

Choose the right marigold varieties

Not all marigolds are the same. Some are more fragrant than others. By a process of trial and error, people have realized the French marigold is the most efficient or the marigold most worth planting to keep aphids away.

French marigolds

The French marigold comes in red, yellow, and red-yellow coloring. This plant is highly aromatic. French marigolds are known to deter aphids.

Flowers of the genus are also known to attract bugs that eat aphids such as lady bugs.

The leaves and stems of French marigolds are a bit spicy and with a potent odor, just like the flower. Some of these stems are collected and turned into spices due to their strong odor profile.

African marigolds

African marigolds are mostly yellow although some orange subspecies also exist. These flowers are highly fragrant and even used to spice up foods.

African marigolds similarly deter aphids to French marigolds. Most people can even confuse these flowers since they can look similar with their green sharp leaves.

Also, consider other natural pest repellents

Marigolds can keep aphids away but they can be combined with other plants and natural deterrents. The flowers themselves might only work on a small surface.

Planting garlic and onions might also work well to keep aphids away. Some people prefer to plant ginger and other types of root vegetables that are used in spices to enhance the effect marigolds have on aphids.


Using pesticides against aphids is not the best when it comes to human health. Pesticides impact health on different levels.

Natural pest deterrents tend to be a better choice. If you want an aphid-free garden you might want to consider planting at least a few marigolds across the backyard.

These flowers have a strong odor and they emit toxins that clear out all types of pests, including aphids.

However, you cannot plant any type of marigold as some aren’t fragrant while others don’t deter aphids.

French and African marigolds stand out among the rest when it comes to a potent smell that keeps aphids away. These flowers make aphids turn around at least for a few feet.

Planting multiple flowers across the yard is best. Those solely counting on marigolds should plant them at least 2 months before their plants and vegetables so that marigolds root properly.

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