Marigolds are a bright and cheerful addition to any garden. They’re happy to flower throughout the summer, and are treasured by gardeners. Not only are they a great companion plant, they also deter numerous pests from other crops. Here’s everything you need to know about turning a pack of marigold seeds into aromatic, colorful flowers.
These are some of the easiest flowers to grow. With a minimal amount of effort, even the least green-fingered novices will be rewarded with rows of beautiful blooms.
Marigold Varieties
While there are over 50 known marigold species, most belong to one of 3 varieties:
African Marigolds (Tagetes erecta)
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Also known as American or Mexican marigolds, these are tall, upright plants that produce large, globe-shaped flowers. They thrive in hot conditions, and are an excellent bedding plant.
French Marigolds (Tagetes patula)
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A compact, bushy variety, they are usually wider than they are tall. French marigolds produce elegant, demure flowers that look great when planted in large groups. You can plant them containers or window boxes, or use them as edging for flower beds.
Signet Marigolds (Tagetes tenuifolia)
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Also known as rock-garden marigolds, this compact variety thrives in hot, dry sites. The delicate, daisy like flowers are also edible, with a spicy tarragon flavor. Again, these are ideal for borders and window boxes.
You can plant French and Signet marigolds at any time in the summer. African marigolds take longer to flower, so you need to plant them in spring, for a longer growing season.
Finally, triploid marigolds are a hybrid of the African and French varieties, and produce multicolored blooms.
Many varieties and hybrids are also edible, including:
- Bonanza
- Bon Bon
- Flagstaff
- Lemon Gem
- Tangerine Gem
- Red Gem
*Note: Calendulas are often referred to as pot marigolds. While the two are both members of the sunflower family (Asteraceae), marigolds and calendulas are not interchangeable.
Growing Marigolds
Marigold seeds are easy to germinate and grow. They prefer sunny locations, but will also grow in partial shade. Just note that marigolds in partial shade won’t flower as prolifically as those planted in full sun. Marigolds will grow in USDA hardiness zones 2-11, but prefer the temperature to be above 50℉.
How to Plant Marigold Seeds
If you want to plant marigolds in the spring, start them off indoors 50-60 days before the last frost date. Seeds sown later in the year can also be started undercover.
To sow marigold seeds, fill a tray with damp, fresh potting mix or general-purpose soil. Sprinkle the seeds over the soil before covering with a thin layer of vermiculite. The optimum temperature for germination is 66℉. Place the trays in a propagator or in a warm location, such as on a windowsill or on top of a refrigerator.
Marigold seeds can germinate within 4 days, but it can often take a little longer. Once germination occurs, remove the trays from the propagator and place them in a light location. Ideally, marigold seeds should receive at least 5 hours of light each day.
Keep the soil damp as the seedlings grow.
Once the seedlings have grown two sets of true leaves, they can be thinned out and transplanted into their own pots. Continue to grow the seedlings indoors until the last frost has passed.
Planting Marigolds Outside
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Marigold seedlings should be hardened off before planting. As such, you can use this time to properly prepare the soil.
These plants are tolerant of most conditions, but they do best in moist, well-draining, fertile soil. Prepare the soil by digging over the top 6-8 inches and removing any stones that you find. Working organic fertilizer into your soil in the weeks before planting will help to improve its overall condition.
When ready to plant, dig a hole that’s just large enough to comfortably hold the seedling’s root base. The plant’s leaves should be just above ground level. Before placing the plant in the hole you can add some slow-release, granular fertilizer—a 5-10-5 mix is ideal—to give the plant an extra boost. Marigolds are quite robust, however, so this isn’t totally necessary.
The amount of space each flower needs depends on the variety. While you should check the information on the packet for the exact spacing, generally taller varieties need to be about 15 inches apart, while dwarf varieties require just 7 inches.
Once planted, water the seedlings in well.
If you want to plant your marigolds into pots or window boxes, the process is the same. Just make sure that the plants have enough room to grow. Fill the containers with a soil-based potting mix and, before planting, work in a slow-acting, granular general-purpose fertilizer.
Caring for Marigolds
As your marigold seeds grow, they’ll require a little care and attention.
Watering
Water your marigolds once a week or when the soil dries out. Try to only water the base of the plant, keeping the leaves dry. Watering from above can cause these plants to become soft and water logged. Wet leaves can also encourage disease.
If you are growing marigolds in containers, they’ll require more frequent watering: sometimes as often as once a day.
Fertilizer
If your soil is rich in organic material, then you don’t need to apply a fertilizer. You can improve poor soil by applying a slow-acting, water-soluble or granular general-purpose fertilizer. The amount you apply will vary depending on the type you use, so check the packet. Be careful: over-fertilizing marigolds can encourage excessive foliage growth at the expense of flower production.
Mulching
When the seedlings have established themselves, spread a 2-3 inch layer of mulch around the base of each plant. This will reduce weeds, and the mulch will fertilize the soil as it decomposes.
Weeding and Pruning
Weed the area around your marigolds regularly. When the flowers start to die, remove them by cutting the stem back to the nearest set of leaves. Deadheading will encourage the plant to produce more flowers, extending the growing season.
Also, pinching off the tops of the plants will help to prevent legginess. Instead the plants will become bushier and produce more flowers.
Common Pests and Problems
Once your marigold seeds have germinated, you’ll find that they are largely problem free. In fact, marigolds seem to repel many pests, meaning that they’re a valuable addition to any garden.
That said, occasionally even these hardy plants may come under attack.
Pests
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Mites and aphids may sometimes target marigolds. Spraying the plants with cold water or insecticidal soap every other day for a fortnight should solve even the most persistent infestation. Infestations of spider mites and other soft-bodied pests can be dealt with in the same way.
Slugs also target these flowers, destroying entire plants in just a few hours. Slug pellets, or organic alternatives, will keep them at bay.
Disease
As long as you plant marigolds in well-draining soil and weed them regularly, they’ll be free from disease. One exception to this is that fungal infections can develop on wet leaves. Make sure to water only the base of the plant in the early morning, so that the leaves have time to dry. This should prevent fungus from forming.
Marigold Companion Plants
These flowers do well with a number of other flowers including:
- Allium
- Asters
- Clematis
- Geranium
- Gerbera
- Lantana
- Lavender
- Roses
- Salvia
- Zinnias
Marigolds also seem to benefit a number of vegetable plants. For this reason they are a common sight in vegetable gardens and allotments. Vegetables that benefit from marigold companion planting include:
Herbs, such as basil, also do well when grown close to marigolds.
Plants to avoids
One of the few vegetable that struggle when planted near marigolds is beans.
Some people advise that cabbage and broccoli shouldn’t be planted near marigolds. While other people have had great success with this combination bear it in mind when planning your vegetable garden.
Harvesting and Storing Marigold Seeds
Saving marigold seeds for sowing the following year is an easy process. Just be aware that if your marigolds are hybrids, the results will be unpredictable. Hybrids are developed by cross-breeding, meaning that the seeds will produce flowers similar to only one of the parent plants.
If you want to cultivate carbon copies of the previous year’s flowers, then save seeds from heirloom, open-pollinated plants. Hybrids can also struggle to germinate the following year.
The ideal time to harvest seeds is when the flower petals turn brown and have dried out. The base, or seed pod, should be turning brown as well.
Remove the dried flower head from the stem, then carefully pull away the dried petals and leaves. Only the slender, pointy, two-colored marigold seed should be left attached to the base.
Next, separate these seeds from the base of the flower and spread them on a paper towel to air dry. This will take about a week, and prevents rotting in storage. You don’t need to cover the marigold seeds while they’re drying.
Once dry, place the seeds in a plain, paper envelope and store that in a dry, cool place. For the best results, use these seeds in the next growing season. The older the seeds, the more difficult they are to germinate.
Now that you know how to save and cultivate these seeds, you’ll be able to grow stunning flowers year after year. Be sure to share extra seeds with friends and neighbors too!
