Aside from its beautiful and colorful appearance and many benefits, nasturtium is also easy to grow. No wonder it’s one of the most recommended flowers to grow for first-time gardeners, especially those who think they don’t have a green thumb.
So, when to plant nasturtium seeds? Start nasturtium seeds indoors if there’s no frost for the last two to four weeks. For planting nasturtium seeds outside, sow the seeds one to two weeks after the last spring frost date.
Table of Contents
Best Time to Plant Nasturtium Seeds
For first-time gardeners who are planning to grow and see beautiful nasturtium flowers in their garden, there are three things you should consider. Those are your region, your region’s hardiness zone, and the type of nasturtium seeds you’re planning to grow.
If you’re in California or other regions with mild winters like Hawaii, Florida, and Texas, the best time to plant nasturtium is during spring.
- To be more specific, you can plant outside from May to June, which is approximately two to four weeks after the last frost date, to make sure your seeds survive the cold.
- If you want to start nasturtium seeds indoors, make sure to plant your nasturtium seeds in well-drained but moist soil about four to six weeks before the last expected spring frost date in your region to make sure that your nasturtium is ready for transplant come spring.
For cooler areas such as Alaska, Dakota, and Wyoming:
- You can start nasturtium seed indoors and place it in the brightest area of your house. Or you can sow your seed outside under cover (to protect it from slugs or any kind of animal) from March to April. It is for them to be ready for transplant when the temperature gets warmer.
Remember, the nasturtium plant thrives best in places with a temperature between 55° and 65°Fahrenheit. The lowest temperature it can tolerate is 30° to 40° Fahrenheit. The nasturtium seed will not survive in temperatures lower than that.
2. Hardiness Zone
Aside from the temperature, it’s also essential to know the hardiness zone in your area.
Why is it important to know your hardiness zone?
You will know the plants you want to grow can survive and thrive in your area. It will also help you identify when to plant your nasturtium seeds specifically.
- If you’re in zone 3, and zone 4, the best time to start indoors is from April 1 -15, and plant outdoors/plant seedlings/transplants outdoors on/around May 15.
- If you’re in zone 5, zone 6, and zone 7, the best time to start indoors is from March 1 -15, and plant outdoors/plant seedlings/transplants outdoors on/around May 15.
- If you’re in zone 8, the best time to start indoors is from February 1 -15, and plant outdoors/plant seedlings/transplants outdoors on/around March 15.
- But if you’re in zone 9, zone 10, and zone 11, you can start four to six weeks indoors before planting outside, and you can plant outdoors/plant seedlings/transplants outdoors all year round.
3. Annual and Perrenial Nasturtium
Lastly, aside from your region and hardiness zone, the best time to plant nasturtium depends on the type of nasturtium you want to grow.
- Annual Nasturtium
For annual nasturtium, it’s best to start the seeds indoors about four to six weeks before the last spring frost.
But if your nasturtium is already ready-grown bedding, then it’s best to plant it outside from May to June.
Plant the nasturtium seed in well-drained soil. But note that although the nasturtium seeds want moist soils, you have to be careful not to over-water, or they will produce subpar color and flavor.
Types of annual nasturtium flowers:
- Alaska Flowers – a vibrant flower; its color ranges from yellow to red.
- Firebird – from the name itself, its color variation is red and orange.
- Whirlybird – has a wide range of colors from red, yellow, and orange; it’s also a semi-double flower (meaning it has double or triple the number of petals as an ordinary flower).
- Tom Thumb – like the Whirlybird, it also has a wide range of colors, but it’s smaller and only produces single flowers.
- Empress of India – it’s a climbing or trailing annual that produces a scarlet-red flower.
Now, you may like this guide on when to plant flowers.
- Perennial Nasturtium
Unlike annual nasturtiums, perennial nasturtiums can survive the cold. Therefore, gardeners in cooler areas, start nasturtium seeds from March to April, then transplant the seeds when the temperature gets warmer.
Type of Perennial Nasturtium
- Mashua – its color is similar to that of the common nasturtium plant. Still, you can eat its leaves, flowers, and tuber, and it is treated as a root crop in South America.
- Hermine Grashoff – it has double orange-scarlet-colored petals.
How Long Does It Take Nasturtium Seed to Sprout?
The nasturtium germination time is between seven to twelve days, sometimes longer for outdoor nasturtium. If you want to see your seeds sprout properly, please remember these important facts:
Other Important Things to Remember When Planting Nasturtium
Nasturtium flowers can survive in infertile soil if they have sufficient drainage. It can stand dryness, but this plant prefers moist soil.
Whether you’re planning to plant nasturtium indoors or outdoors, you must ensure that you sow your nasturtium seed about half an inch deep in warm soil.
If you planted your seed outdoors, make sure that there are at least ten to twelve inches of distance from each seed for your seeds to germinate properly.
It takes about thirty to thirty-five days to grow nasturtium indoors before it’s ready for transplant to your garden.
The nasturtium plant loves the sunlight, so if you’re planning to plant your nasturtium seeds indoors, make sure that it gets enough sunlight. Make sure that it gets six to eight hours of sun exposure. Lesser than that will result in subpar bloom.
Water your plants regularly, about one inch per week, but don’t overwater your seeds. Remember that all over-watered plants have subpar blooms and less flavor.
5. Temperature and Humidity
As mentioned before, the nasturtium plant thrives best in places with a temperature between 55° and 65°Fahrenheit. The lowest temperature it can tolerate is 30° to 40° Fahrenheit. The nasturtium seed will not survive in temperatures lower than that.
So, what should you do if the frost comes after you planted your nasturtium seed? Don’t panic because you can do something to help your seeds survive.
- Bring all potted nasturtium seeds indoors and put them in the warmest area of your house.
- Cover your nasturtium seeds with burlap if you have directly sowed your seeds in the ground. Ensure that it’s appropriately covered and that the wind or any animals won’t be able to take the cover off.
As the nasturtium plant thrives best in sandy but moist soil, you should avoid using fertilizers. They produce subpar flowers and flavor if planted in soils with organic matter. Again, nasturtium likes the sun and would bloom beautifully in infertile soils.
From the leaves to its flowers, the nasturtium plant is one of the most useful plants you can add to your garden.
Now that you know when to plant nasturtium seeds, you can start adding the nasturtium plant to your garden. Imagine eating a flavorful salad while looking at your beautiful garden. Isn’t life amazing?
Moreover, there are other flowers that are also great choices for your garden. Check out the best times to plant them below:
I hope this article helped you as you begin your gardener journey. Tune in for more gardening tips. Happy digging!
Hello, my name is Dorian Goodwin and I have worked as a gardener and groundskeeper for the past 12 years. You can count on me for expert guidance on how to care for your garden. Creating a lush lawn for your front yard or growing an array of colorful flowers for your garden is a labor of love that I fully appreciate. And I am here to help.