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Learning how to grow marigolds from seed can broaden the array of beautifully colored marigolds available for you to plant in your garden. By planting marigolds from seed, you can shop from the wide assortment of marigolds available only from seed rather than being limited to nursery varieties. You can also apply your knowledge as you learn how to grow marigolds from seed to grow other flowers like strawflowers, gomphrena, scabiosa, and more. The joys of growing a garden are amplified by the ability to start flowers from seed. You can fill your garden with color and blooms year-round at a fraction of what it would cost to buy the flowers from a nursery. In this blog, you will not just learn how to grow marigolds from seed but also how to start many other flower seeds.
Marigold seeds are thin and long and can easily be planted too deeply. When growing marigolds from seed, this is a very important factor to remember, many gardeners accidentally cover their small marigold seeds with too much soil or clumpy soil filled with sticks and large particles that keep seeds from sprouting. We suggest you start your marigold seeds in starter pots with a high-quality seed starting mix for the best results. If you have taken our seed starting class, you know that one of the most important factors in easily starting seeds is using a high-quality seed-starting mix like our Black Gold Seed Starting Mix. This allows the seeds to easily and quickly germinate while holding in precious moisture essential to seed starting. If you are a beginning seed starter, please take the time to learn about seed starting from our many educational resources.
YouTube: Seed Starting Tutorial
Blog: Successful Seed Germination
Blog: Planting Seeds for Beginners
Class: Seed Starting Academy
You can find these blogs and many more in the seed starting section of our Garden Wisdom Blog.
Starting Marigold Seeds
Take the time to learn about seed starting from these resources. You will see that the keys to understanding how to grow marigolds from seed are planting in a high-quality seed starting mix, watering regularly, and allowing adequate light so that the seedlings are not lanky. Once your seedlings have emerged and you see their first true set of leaves, it is time to fertilize!
We recommend you regularly fertilize with a diluted organic fertilizer like our fish emulsion. Simply dilute the solution by adding twice as much water to the mixture. You can use this to fertilize your seedlings each time you water. This system of watering and fertilizing at the same time is called fertigation. This allows for the small plants to absorb nutrients regularly and grow quickly. We use this method on our farm for all seeds that begin in starter pots. We aim to get them up and growing as soon as possible and out into the garden. By regularly feeding them, we can guarantee that it will happen.
Once your seedlings have filled up a 4” pot with roots and are at least 3” and healthy, it is time to plant them outside. Marigolds love the heat and can be succession planted throughout the summer and into the fall in Zones 9 and 10. If you are transplanting your seedlings out in the summer, prepare them for this adjustment by hardening them off first. This process exposes them to outdoor temperatures and sunlight for an increasing amount of time each day. We recommend a week of hardening off before planting them into the garden.
Transplanting Marigolds Grown from Seed
Now that you have taken the time to learn how to grow marigolds from seeds, do not be too hasty and simply transplant them out into the garden during the heat of the summer.
We always recommend taking the following considerations before you plant any starts out.
- If temperatures will reach over 85 degrees, plant your seedlings out in the cool of the evening instead of in the morning or heat of the day.
- Always, ALWAYS, water well before, during, and after planting. If heat and dryness are excessive, use shade cloth to protect your transplants in their first few days of growing. During the first week of growing, it is important to peek at your newly transplanted marigolds and make sure they are getting adequate watering. Once they are established, they will grow happily and easily in the garden.
- Harvest the blooms often for the most brilliant display of color and deadhead when the flowers are spent.
When to Plant Marigolds in the Garden
In Zones 9 and 10, marigolds can easily and happily grow in the frost-free days of June through late October. In other zones, start your seeds indoors 5–6 weeks before the last frost to get them up to size. Then plant them out into your frost-free spring or summer garden.