When to plant nasturtium seeds - Experts reveal the perfect time to sow these edible flowers

Nasturtiums are a welcome addition to any garden. Not only are they vivid in colour and quick to grow, but everything from the flowers to the leaves is edible. But if you want to grow nasturtium, you need to know when to plant nasturtium seeds. 

In our opinion, the best garden idea is one filled with colourful flowers. And nasturtiums offer almost every colour of the rainbow. They’ll bloom from midsummer to early autumn, filling your garden borders or hanging baskets with reds, yellows, pinks, oranges, and more. 

Thankfully, nasturtiums are also very easy to grow. As long as you plant nasturtium seeds at the right time, you’ll be rewarded with stunning annuals that will take over your outside space and give it the summer boost you (and your garden) need. 

When to plant nasturtium seeds

You can typically buy nasturtium seeds in bush or climbing varieties, but the sowing period is exactly the same. In fact, you have a fairly large window to complete this garden job, as the best time to plant nasturtium seeds is between March and May. 

Ideally, you should add this to your list of garden jobs in April to ensure you don’t forget and that the last of the late winter frosts have passed. That’s because nasturtiums are extremely sensitive to the cold and prefer to be out in the warm sunshine.

However, this ultimately depends on how you plan to plant nasturtium seeds. Steve Chilton, garden expert at LeisureBench explains, ‘Nasturtium seeds should be sown inside from March, while outside from late March/April to May. I recommend waiting until it warms up a bit before planting them outside, which is why late March/April - May is a good time.’

If you can, try to stick to this schedule. If you don’t, your blooms may suffer. Craig Morley, a gardening expert from Budget Seeds, says, ‘Like any other seed, if nasturtiums are planted outside of their ideal sowing time, then they are unlikely to sprout, even if the seeds are still viable. When the soil is cooler and temperatures are lower, the seeds may be less likely to germinate and could potentially rot if the soil is wet.’

This timing also works in your favour if you’re growing your own fruit and vegetables this year. In fact, they’re ideal for companion planting as animals love nasturtiums. And all the time these critters are munching on the leaves of these flowers, they’re staying well away from your beloved produce.  

To ensure a successful sowing session, though, it’s always a good idea to soak your nasturtium seeds in water for 24 hours prior to planting. This will soften the hard outer coating of the seed and allow for better germination. 

And when you’ve sown your nasturtium seeds, you have the advantage of leaving them to their own devices. Craig says, ‘After they have begun to grow, nasturtiums are relatively easy to care for and require little maintenance, as plants growing in the ground outside will rarely need watering.’

‘However, if you want to encourage the plants to bloom more you will need to deadhead them for flowering over a longer period of time. Additionally, if you live in a milder area, there is a chance that your nasturtiums may self-sow, so you could see more seedlings appear in the future.’

Steve Chilton

Steve is a passionate and knowledgeable garden expert with several years of experience within the field and has developed strong expertise for all things nature and plants. Steve is a keen educator and loves to share this knowledge with others. He strives to simplify complex garden practices and encourage eco-friendly gardening.

Where to buy nasturtium seeds

• Sarah Raven - Pick up 25 seeds for £1 or invest in a nasturtium mix
• Suttons - Try the enchanting Lady Bird nasturtium seeds
• Crocus - Buy 40 climbing nasturtium seeds for £2.29

FAQs

What is the best month to plant nasturtium?

The window to plant nasturtium is relatively large, and you have between March and May to do so. You could also wait until June to plant nasturtium, but this may shorten its flowering season. 

Because of this, April is the ideal time to plant nasturtium. By doing so in April, you can make sure that the cold temperatures have passed and that they have enough time to establish themselves before the summer flowering season. 

Can I plant nasturtium seeds now?

You should aim to plant nasturtium seeds between March and May for the best results. Any earlier than that and the temperature will be too cold, but any later than that and you’ll shorten the flowering window. 

To successfully sow your seeds, most experts would suggest starting them inside before transplanting them outside after germination. However, you can also plant them directly outside if you don’t have the space. 

Do nasturtium seeds need to be soaked before planting?

Yes, you should soak nasturtium seeds before planting. This will soften the hard outer coating of the seed and allow for better germination. Ideally, you should soak them for 24 hours before sowing. 

Now you know when to plant nasturtium seeds, it’s time to get sowing!