Coleus Seeds: How to Start a Coleus

Written by Phil Dubley
Updated: November 15, 2022
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Growing your own plants from seed is always a rewarding experience, and coleus shrubs are ideal for this. There are myriad species that vary wildly in colors, patterns, and shapes, but how do you grow them? And what care do they need?

Luckily, coleus plants are easy to grow and require little care. Seeds can take up to 20 days to germinate, but seedlings will turn into fully grown plants in three to four weeks. It is best to plant them in early spring to make good use of warm weather.

Read our step-by-step guide to growing your coleus plants from seed.

Coleus SeedsHow to Grow
Hardiness Zones10 and 11
Number of Coleus VarietiesOver 1,000 varieties, the most popular ones being “French Quarter,” “Rustic Orange,” and “Henna”
Time of Year to Germinate SeedsGerminate them eight to 12 weeks before the last frost date
Time of Year to Plant SeedlingsStart them in indoor pots and transplant them once temperatures reach at least 60 degrees F
Things to NoteColeus are tropical plants and are sensitive to cold! If you keep them indoors, they can last for up to four years

Germinating and Growing Coleus Seeds

Growing coleus from seed is a simple process, although it takes some time to germinate. These plants are great for beginner and experienced gardeners alike, but you will need to repeat this process every year if you live in a colder area. Here’s how to do it:

  • Choose your growing pots — You can use seed trays filled with a well-draining potting mix. Put three or four seeds in each container, but do not fully cover them with soil.
  • Start your seeds indoors — As tropical plants, coleus requires light and warmth to germinate. Keep the soil damp but not wet, and ensure the pots are always at 700 to 75 degrees F.
  • Care for your seedlings — Seeds can take up to two weeks to sprout. Once the seedlings get at least two sets of leaves, transplant them into separate pots.
  • Harden the seedlings — One week before moving them to the garden, gradually expose the seedlings to the outside environment to ensure they survive.
  • Plant them in your garden — Choose an area with partial shade to dig a hole wider than the current pot and place the young coleus inside. Water immediately to avoid shocking the plant.
baby coleus plants

Before you move your coleus outdoors, you want to harden them off — that is, get them used to the outdoors for several hours a day leading up to the transplant

©iStock.com/Lena_Zajchikova

Harvesting Coleus Seeds

Most people use coleus as an annual plant because they die easily when temperatures drop. If this is your case, you will surely be interested in harvesting the seeds for the next year.

Before fall, choose a few of the healthiest plants to collect their seeds and identify them with a string. Once the flowers come out, do not remove them! Allow the seed pods to wither and dry out.

When the petals fall out, and the pods turn brown, you know it’s time to harvest. Snip the pods with scissors and place them in a paper sack. Keep the sack in a cool and dry area, and shake it every day to avoid seeds sticking to the flowers.

After a week, the tiny seeds should be dry and ready for storage. Remove any plant debris and keep them in a dark, cool, and dry area until they’re ready to be planted again.

With gorgeous foliage and endless combinations of patterns, coleus plants are the perfect addition to any garden and home. Smaller ones can add color to a room, while bushier varieties will create a backdrop for flowers or even another coleus!

These are some of the most popular coleus varieties:

  • French Quarter: Big leaves with the classic combination of a green edge and bright pink center that fades into burgundy. This variety grows up to 30 inches.
  • Black Dragon: A smaller variety of 12 inches, with dark ruffled leaves in purple hues.
  • Henna: Its serrated leaves possess gold shades with a burgundy underside that reaches the edges. It can reach 24 inches in height.
  • Wasabi: A tall 30-inch variety with a solid bright green color that is the same shade as wasabi. 
  • Campfire: The pointy, serrated leaves grow up to 20 inches and have an orange-red color similar to rust.
  • Wizard Rose: The green leaves have bright pink centers that are surrounded by white. It is a small variety that won’t grow past 14 inches.
  • Electric Lime: Popular and versatile. Its medium green leaves have yellow veins running through them, and they can grow up to 24 inches.

Want to learn even more about this amazing plant? Check out our complete guide to coleus here.

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The photo featured at the top of this post is © iStock.com/wasja


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About the Author

My name is Phil Dubley, I am a Canadian living in Argentina, but tomorrow I could be writing from anywhere else. Throughout my life, I've been in love with nature: plants, animals, people, and everything in it. I have a passion for wild animals - snakes, sharks, and felines have always fascinated me. As for plants, I love succulents. I have a collection of over ten different varieties on my terrace. Also, I use the hemp plant as CBD oil for sleep: it has been the only thing to tackle my insomnia effectively. I want to share all my knowledge about the areas I am passionate about with others who feel the same way. I hope you enjoy my articles, and in each one, you learn something new!

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Sources
  1. Gardening Know How, Available here: https://www.gardeningknowhow.com/ornamental/foliage/coleus/coleus-plant-blooms.htm
  2. Napa Master Gardener Column, Available here: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28449#:~:text=Coleus%20seeds%20need%20light%20and,keep%20between%2070%C2%BAF%20and%2075%C2%BAF
  3. Farmer's Almanac, Available here: https://www.almanac.com/not-your-grandmas-coleus