3 Reasons Why Marigolds Need Full Sun And Not Shade

Orange marigolds flower fields, selective focus

Do you have your own vegetable garden? If so, there is a good chance you have marigolds planted somewhere. Traditionally, marigolds help draw insects and animals away from your juicy vegetables. Whether you’re a new or experienced gardener, it’s good to know how much sun these flowers need.

Marigolds need at least six hours of sunlight each day. They can grow in partial shade but in order to grow multiple flowers and bloom throughout fall, marigolds need full sun. Planting them in full sun will promote lush and dense plants while increasing their production of blooms.

We’ll get into depth about why marigolds need full sun and shade and how you can grow strong, full marigolds. Keep reading to keep your marigolds big and blooming!

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Reasons Marigolds Need Full Sun

Marigolds are indigenous to Central and South America where they were discovered during the 1500s. From there, marigolds were brought to Africa and Europe resulting in species like the African and French marigolds. 

Because of their indigenous climate, they can tolerate drought and love sun-filled days. Although some species can tolerate part shade, it’s unlikely that you’ll achieve the full, dense look that you’re going for with your marigolds unless they have more access to the sun.

So before you begin planting this summer, lay out your marigold plants in areas that you know have full sun and you’ll have marigold dreams!

Marigolds Need Full Sun To Photosynthesize All Day

Marigolds are dense with foliage. Have you ever seen the leaves on marigolds? They are a work of art on their own, and they even look like some herbs! Because they have such dense, dark green foliage, they are constantly photosynthesizing throughout the day. This helps the marigolds continuously grow multiple flowers at once.

Certain types of marigolds even have double flowers. Yes, you heard that right! African marigolds, French marigolds, and pot marigolds all can bear double flowers.

So, they need full sun to put the energy into and grow these dense double flower heads. And since marigolds continue to flower throughout summer and fall, they need full sun to continue to photosynthesize throughout these seasons.

Marigolds can continue flowering into late fall. But to do this, they have to be deadheaded, which is simply removing flower heads when they’re done blooming. So, you can see why they need full sun, to keep growing those flower heads all year long!

Full sun allows marigolds to grow strong and full, without it, they probably won’t flower and become leggy!

If you’ve ever smelled marigolds, you know just how fragrant they are. Aside from growing dense foliage and flowers, the scent of marigolds is also dependent on the amount of sun they get, similar to lavender and other fragrant flowers. 

According to the United States Department of Agriculture, fragrant floral scents are a mix of VOCs (volatile organic compounds) and essential oils that are emitted into the atmosphere to attract pollinators.

These essential oils evaporate from the petals in warm weather releasing a floral scent. And what does the sun have to do with this? Evaporation! The more sun there is, the more evaporation there is!

Not all flowers that grow in the sun produce a scent, like sunflowers, dahlias, or hibiscus. Even flowers that are shade tolerant can be fragrant, but they typically are exposed to, and require a little sunlight, thus, releasing some floral scent. 

Whether you decide to plant only marigolds or want to venture into other full sunflowers, the Burpee Wildflower Mix Monarch Sanctuary 50,000 Seeds is an ideal choice! 

This seed mixture comes with over a dozen types of flowers including marigolds, butterfly weeds, zinnias, and Mexican sunflowers, to name a few. It comes with enough non-GMO seeds to cover 1,000 square feet. 

And, the most important part is that it’s a wildflower assortment to attract pollinators and help monarch butterfly populations by providing them with this incredible batch of flowers.

Marigolds Need Full Sun To Prevent Wilting And Pests

Marigolds in full sun

Common Marigold Issues

Marigolds are prone to things like leaf spots, wilt, blight, root rot, and aster yellows, without proper sun and drainage. They are also susceptible to pests like the imported long-horned weevil, the potato leafhopper, and plant bugs.

  • Leaf spots are caused by a fungal affliction and can vary depending upon the specific pathogen. This can be avoided, however, by making sure your plant is strong and healthy. You can do this by proper planting location, and fertilizing.
  • Next up, we have wilt. This is another fungal infection that can come from Verticillium or Fusarium oxysporum. Wilt causes wilting of lower leaves and leads to the death of the marigold. Sometimes plants won’t show any signs until it’s too late. This can also be avoided by making sure you have strong and healthy plants, and not damaging the roots.
  • Botrytis blight is pretty gross-looking because it looks like mold. Marigold flowers begin turning brown and are covered with fuzzy, gray blobs. This fungus occurs whenever there’s lots of humidity, moisture, wetness, and lack of sun.
  • Root rot is one that we’ve touched on before, and it usually affects indoor plants. But don’t let that fool you! Root rot can occur just as easily outside as it can inside, especially due to overwatering!
  • Lastly, we have aster yellows. This pathogen is caused by phytoplasmas, which are an intracellular parasite that affects the phloem of plants. This is transmitted through leafhoppers, a common pest of many plants. This disease results in small, oddly shaped, stunted plants.

Common Marigold Pests

The imported long-horned weevil lays its eggs in the soil and feeds on the roots of mairgold plants as larvae. When they become adults, they start feeding on the edges of leaves or flowers. 

The potato leafhopper is a sap-sucking insect that feeds on marigold foliage causing it to whiten and shrivel up. Also, as we mentioned, this pesky insect can transmit aster yellows.

Plant bugs. It sounds like a made-up name, but these bugs lead their eggs in the stems of marigold plants. When they hatch, they suck the sap from leaves eventually turning into circular holes. 

Most of these issues can be avoided by maximizing plant vigor and keeping your marigold healthy.

With that, one of the easiest ways to keep your plant healthy is to plant it in the proper location, in this case, in full sunlight, to help your marigolds grow big and strong!

Since we’re talking about pests, if you’ve ever worked outside during the summertime, you probably know just how bad the bugs can be. Gnats and mosquitoes especially! And if you don’t know, well let’s just say, this is your hint! 

With a bug repellent like Bug Soother Spray – Natural Insect, Gnat and Mosquito Repellent & Deterrent, you can be protected without all of the chemicals in other bug sprays with a nice and pleasant scent!

Marigolds Need Full Sunlight To Control Soil Moisture

Marigolds can tolerate a variety of soil types and humidity levels, especially depending on their type. However, most marigolds grow best in well-draining, acidic soil, and won’t do well if left in saturated, water-logged soil.

Standing water in the soil can be a direct result of lack of sunlight and poorly-draining soil. Marigolds can tolerate a little bit of shade, especially if they are newly transplanted. But if they’re going to stay in a partially shady location, they need well-draining soil.

As we mentioned, some of the pathogens above are a direct result of humid and overly wet conditions that don’t have a chance to dry out. If over-watered, or planted improperly, you are setting your marigolds up for failure instead of success.

Can Marigolds Grow In Shade?

Marigolds in shade

Marigolds can be grown in some partial shade, however, they will have the most success in full sun. Now, when we say partial shade, we mean anywhere from 3-6 hours of direct sun. Some partial shade can help lessen the heat in really hot and sunny places.

Even though some marigold varieties can thrive in partial shade – if you want to grow strong, vigorous plants, your best bet is to plant them in an area that will get at least three hours of direct sun, preferably six hours!

If you are looking to add more shade to your yard, you can learn more about the fastest growing shade trees for small yards.

Next, we’ll cover some common types of marigolds. 

Most Common Types Of Marigolds

French marigold bloom flowers

So, there are two main species of marigolds, the African marigold, and the French marigold. African marigolds are tall, large plants, with fairly big blooms.

French marigolds, on the other hand, are smaller, more compact, and probably the type you see most often.

There are also hybrid marigolds, which are a cross between African and French marigolds, which range in size and shape.

African Marigolds, Tagetes erecta

African marigolds are usually referred to as American marigolds. They have double flowers and grow up to three feet tall! This species of marigolds also can have five-inch blooms. 

French Marigolds, Tagetes patula

French marigolds are probably the most common. They have single flowers and are more compact.

These are the marigolds you have probably seen at hardware and garden stores that come in yellow, dark red, orange, and a combination of all these colors. 

These are small marigolds that range in sizes from six inches up to 18 inches. This type is more tolerant of moist conditions.

A few varieties of the French marigold include ‘Bonanza’, ‘Little Hero’, ‘Bounty’, ‘Hero Orange’, and ‘Queen Sophia’.

Hybrid Marigolds

Hybrid marigolds are French and African marigolds that have been crossbred. They range in a variety of sizes, colors, and shapes such as signet marigolds and Spanish tarragon!

That’s A Wrap!

Marigolds are the perfect addition to your garden, vegetable bed, or even to grow in pots. They will give off that incredible smell and add a pop of color wherever you decide to plant them. 

Marigolds come in all shapes, sizes, and colors, and so many varieties it’s hard to pick a favorite.

Remember, wherever you decide to plant them, make sure they’ve got full sun.

Let’s recap a few things we discussed!

Marigolds need at least 6 hours of sunlight each day to thrive and grow luscious, sweet-smelling blooms. 

Marigolds can grow in partial shade but to grow multiple flowers, and bloom throughout the seasons, they need full sun. Planting marigolds in full sun will promote strong, dense plants, and make them less susceptible to pathogens and pests.

You can choose from African marigolds, French marigolds, or a hybrid variety, all of which have the same light requirements: Sun!

Thanks for sticking around and learning why marigolds do not grow in the shade and why they need full sun. We hope this helped you in your marigold adventures, until next time!

References

Atiyeh, R. M., N. Q. Arancon, C. A. Edwards, and J. D. Metzger. “The influence of earthworm-processed pig manure on the growth and productivity of marigolds.” Bioresource technology 81, no. 2 (2002): 103-108.

Broschat, Timothy K., and Kimberly K. Moore. “Phytotoxicity of several iron fertilizers and their effects on Fe, Mn, Zn, Cu, and P content of African marigolds and zonal geraniums.” HortScience 39, no. 3 (2004): 595-598.

Conboy, N. J., McDaniel, T., Ormerod, A., George, D., Gatehouse, A. M., Wharton, E., … & Tosh, C. R. (2019). Companion planting with French marigolds protects tomato plants from glasshouse whiteflies through the emission of airborne limonene. PloS one, 14(3), e0213071.

Hongpakdee, P., & Ruamrungsri, S. (2015). Water use efficiency, nutrient leaching, and growth in potted marigolds affected by coconut coir dust amended in substrate media. Horticulture, Environment, and Biotechnology, 56(1), 27-35.

Sturz, A. V., and J. Kimpinski. “Endoroot bacteria derived from marigolds (Tagetes spp.) can decrease soil population densities of root-lesion nematodes in the potato root zone.” Plant and Soil 262, no. 1 (2004): 241-249.

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