I have a personal interest in marigolds, and I’m always recommending them to my friends as my favorite house and garden plants. After all, their bright yellow and orange flowers are perfect for indoor and outdoor aesthetics, and the plants are perfect for all kinds of gardeners. However, a common question most people ask me is if the marigolds need heat to germinate.
Marigolds don’t need heat to germinate or thrive. And although they’re primarily regarded as summer plants, marigolds prefer soil temperatures between 70oF and 75oF (21.1oC and 23.9oC). However, some potted marigolds will only germinate at temperatures between 50oF and 65oF (10oC and 18.3oC).
In the end, it’s better to maintain room temperatures if you’re growing or keeping marigolds; else, you’ll risk having dormant seeds in your pot or garden. Fortunately, I wrote this article to give you all the information you need to grow marigolds and tips to ensure they germinate and thrive. Let’s get right into it!
How Long Do Marigolds Take To Germinate?
Of course, you can determine if the soil temperature is suitable for growing plants by using a thermometer or planting at an optimal time. For marigolds, the best time to plant them is at the beginning of spring, just as temperatures are starting to rise, to ensure they germinate and flourish into beautiful plants. However, how long do these plants need to grow out of the soil?
Marigolds typically take about 6 to 14 days to germinate and around 8 to 10 weeks to reach full maturity–provided they’re well planted. While the exact timeline depends on the marigold species and environmental conditions, they’ll bloom through the summer and into early autumn.
However, you must ensure the environmental conditions are perfect before you even attempt to plant your marigolds. I also recommend you get familiar with the exact species of marigold you’re keeping so you can track what counts as normal growing conditions and behavior for the plant.
After all, it’s not unheard of to have problems with growing marigolds. These problems are typically developmental and flowering issues, but they’re easy to fix and prevent. I already wrote two articles covering how to fix marigolds with stunted growth and another to help if you’re having problems getting your marigolds to bloom.
What Kind of Marigolds Can You Grow?
There are at least 55 species of marigolds in the world. And while each variant differs slightly in appearance and height, they’re all grown in pretty much the same way. However, all marigold species need pretty much the same amount of time to germinate, mature, and bloom. In the US today, most marigold gardeners and plant keepers usually keep at least one of 5 species of the plant.
Here are the kinds of marigolds you can grow in your home or garden:
- African marigolds
- French marigolds
- Mexican marigolds
- Signet marigolds
- Triploid marigolds
Let’s see how these marigold varieties differ and how you can quickly identify them in gardens and planters.
African Marigolds
African marigolds are one of the most recognizable varieties, and they’re sometimes called Aztec marigolds or American marigolds, depending on which gardener you ask. However, African marigolds are pretty much like every other marigold species, except they tend to grow higher than most variants.
You can recognize this variant by its extensive, colorful flowers that sit on top of shoots that are usually 1 to 3 feet (30.5 to 91.4 centimeters) tall. And while these flowers are unmistakable, the African marigold is also deer-resistant.
The plants, like other marigolds, flourish in well-draining soil but prefer to dry out between watering sessions. Unfortunately, despite their good looks and success, African marigolds are prone to root diseases, particularly root rot from soil fungi.
French Marigolds
French marigolds are pretty similar to African marigolds, and they’re grown in several parts of the United States as well as in various regions in the world. Although they’re quite common varieties, they’re still gorgeous plants that turn your garden into a fantastic spectacle when they bloom.
However, French marigolds aren’t popular just because of their incredible beauty–they’re also simple to cultivate. Therefore, they’re usually the go-to species for new gardeners and plant keepers.
The plants typically grow to reach between 6 and 12 inches (15.2 and 30.5 centimeters) when mature, but they bloom far longer than most marigold varieties. French marigolds will bloom past autumn and into early winter until the temperatures get too frigid. Of course, they’re also deer-resistant like their African siblings.
Mexican Marigolds
The Mexican marigold is a somewhat peculiar species–and not just because they’re perennial plants. Its flowers and leaves are broader and flatter than its siblings, although it does share the bright foliage of every other marigold plant species. Mexican marigolds also have scented leaves that help bring pollinators like butterflies and bees.
However, the plant typically grows to reach heights of between 4 and 6 feet (122 and 183 centimeters), which is much taller than other marigold variants. Still, Mexican marigolds are pretty stable, so you’ll have tall, musky flowers if you decide to keep them.
And like other marigolds, the Mexican marigold thrives on soil with good drainage and under full sunlight. They’re also deer-resistant and can brave dry spells, but they’ll flourish in situations where they can get lots of water.
Signet Marigolds
Signet marigolds are the runt of the litter in this line-up. And although they grow beautiful flowers, Signet marigolds don’t grow more than a few inches when they mature. So, they’re typically delicate and small variants.
Still, signet marigolds grow fantastic flowers that are edible and combine well with most salads and several other dishes. You’ll need to keep them under full sunlight if you want the plants to thrive, but they prefer moist soil to flourish.
Triploid Marigolds
These species of marigolds are actually hybrids and a cross between African marigolds and their French variants. Their foliage is much larger than both parent varieties, and Triploid marigolds produce substantial and enormous flowers that dwarf African and French marigolds.
However, Triploid marigolds are more challenging to grow because they need special care, specific growing conditions, and a more extended growth season than some other marigold varieties. They also don’t germinate as easily as other variants.
Still, it’s possible to successfully keep Triploid marigolds as long as you give them the proper care. Fortunately, this undertaking is usually worth it since this marigold variant thrives in intense heat and will flower in low-light conditions. Therefore, they’re perfect for hotter regions of the Globe.
How To Grow Marigolds
You can grow marigolds from seeds and seedlings, but it’s better to start them from seeds since you’ll have better control over their early development and be able to plan your garden better. However, you can also grow them from seedlings if you don’t want to get too worked up over quality seeds.
Here’s how you can grow marigolds:
- Find a suitable spot or planter for your marigolds. Remember that marigolds need lots of sunlight, so make sure you pick a great location with at least 12 hours of sunlight if you’re keeping them outdoors. Your potted marigolds are similar but ensure the planters are ample if you’re growing multiple plants.
- Get suitable growing trays to start your marigold seeds. You’ll need to fill up a tray with a seed starting mix.
- Fill the growing tray at least halfway to the top with the seed starting mix. You can add some more starting mix if you like, but ensure it’s at least 1 inch (2.5 centimeters) from the top of the tray.
- Add the marigold seeds to the tray and push them into the soil. Ensure you don’t push them in too deep, but just enough that the starting mix completely covers the seeds.
- Spray some water on the mix to dampen the soil and cover it with a plastic bag. You’ll need to keep this bag on till the seeds start germinating. However, remove it once a day to promote aeration and moisture retention.
- Extract the plastic wrap once the marigold seed starts germinating and place the growing tray under a strong light source. A sunny window would suffice, but you can also use a grow light since the seedlings require about 16 hours of sunlight to thrive.
- Transplant the marigold seedlings into the planter or a suitable spot in the garden when soil temperatures are appropriate. I recommend after early spring frost to ensure there’s no danger to your marigolds. You can also wait until the plants are at least 2 inches (5 centimeters) tall before transplanting them.
- Ensure the plants get plenty of space and water until the soil is soaked. I recommend you keep taller marigold varieties at least 2 feet (61 centimeters) apart. However, shorter variants need only 1 foot (30.5 centimeters) of space between cultivars.
It’s important to note that French and Mexican marigolds produce certain chemicals that are toxic to pests like whiteflies but may harm soil nematodes and several beneficial faunas. Therefore, I don’t recommend planting them near edibles, especially beans.
Final Thoughts
Marigolds don’t need heat to germinate but only grow at specific soil temperatures. So, they won’t germinate if you plant them in any other condition. Fortunately, this article contains all you need to know about starting, growing, and keeping marigolds.
Therefore, you can use it as a guide if you’re growing new marigolds or need quick information about their growing conditions.
