How to Grow Nasturtium Indoors

Co-authored by Rachel Guffey and Hunter Rising

Last Updated: September 1, 2021 References

Nasturtiums are a variety of annual plants with edible leaves and flowers that can add a bit of spice to any meal. While nasturtiums usually only bloom in the summer and fall, you can easily grow them indoors if you want to use them year-round. These plants only require a small amount of care, so they’re perfect if you have a busy lifestyle and not a lot of time. Even though you’ll have to plant new nasturtiums, you’ll be able to use the seeds from your last plant to start growing your new one!

Part 1

Part 1 of 3:

Planting the Seeds

1
Opt for a compact variety of nasturtium. There are many kinds of nasturtium, but some can grow tendrils that are up to 20 feet (6.1 m) long. Avoid nasturtium seeds that have the word “trailing” listed on the bag since they’ll grow and expand the most. Since you’ll have more limited space inside, try to find dwarf or compact nasturtium seeds at your local garden center so they don’t take up as much room.^{[1]
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- Alaska nasturtiums are compact and can have yellow, orange, red, or pink flowers.
- Select Peach Melba nasturtiums for yellow and peach flowers that have a red center.
2
Soak the seeds for up to 8 hours in water. Fill a small bowl with just enough water to submerge the seeds completely. Pour all of the seeds you want to plant into the bowl and leave them alone for as long as 8 hours so they can absorb some moisture. That way, the seeds are more likely to germinate.^{[2]
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- You can also try scratching the seeds’ outer shells with a gardening knife since it may also help them germinate.
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3
Mix a slow-release 5-10-10 fertilizer into potting soil. Nasturtiums are very adaptable plants and can survive in any sort of potting soil you want to use. If you plan on eating your nasturtiums, choose an organic soil to ensure it doesn’t contain any harsh chemicals. Look for a 5-10-10 fertilizer at your local garden center that’s labeled “slow-release”. Stir your potting mix with 1 treatment of fertilizer using a trowel. That way, the soil will absorb nutrients over time so you don’t have to apply it later on in the season.^{[3]
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- You can buy potting soil from your local gardening center.
- Avoid high-nitrogen fertilizers since it can actually harm nasturtiums and stunt their growth.
- You can also plant nasturtiums in a well-draining, tropical blend of soil.^{[4]
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  Rachel Guffey
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  Expert Interview. 5 August 2021.}
4
Fill a 12 in (30 cm) pot with your potting mix. Make sure the pot you choose has drainage holes so the soil doesn’t get too waterlogged. Take your mixture of potting soil and fertilizer and scoop it into the pot with your trowel. Leave about 1 in (2.5 cm) of space between the top of the soil and the pot’s rim.^{[5]
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- Nasturtiums can get easily damaged or injured if you try to transplant them, so avoid trying to start the seeds in a tray.
Variation: Nasturtiums also work great for hanging baskets if you want to have your flowers spill and hang over the edges.
5
Sow 1 seed per pot so it’s ¹⁄₂ in (1.3 cm) deep. Push your finger into the soil in the center of the pot to make your hole. Drop the 1 of the seeds you soaked into the hole and press it down so it makes firm contact with soil. Fill the hole back in with soil before lightly compacting it down.^{[6]
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- Avoid planting more nasturtiums in your pot since they will compete for nutrients and won’t grow as healthy.
6
Water the soil thoroughly. Use a watering can to slowly pour the water onto the soil. Be careful not to disturb the seeds, or else they won’t be able to establish roots. Continue watering the soil until you see it coming out the drainage holes in the bottom of the pot.^{[7]
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- Leave a dish underneath the pot to catch the excess water. The water will eventually absorb back into the soil.
7
Keep the pots above 55 °F (13 °C) in an area that gets 6 hours of light. Look for an east- or south-facing window sill to keep your nasturtiums so they can get sun throughout the day.^{[8]
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Research source}Leave the nasturtium alone while it starts to grow so you don’t disturb the seeds. Make sure the temperatures don’t dip below 55 °F (13 °C), or the seeds may not germinate.^{[9]
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- If you’re growing nasturtiums in the spring or summer, you can keep them outside during the day as long as there isn’t a risk of frost.
- You may also use fluorescent grow lights if you don’t have a sunny window in your home.^{[10]
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  Expert Source
  
  Rachel Guffey
  Plant Specialist
  Expert Interview. 5 August 2021.}
8
Look for sprouts within about 10 days. Continue watching the pot over the next week as the sprouts start forming. You should notice small green shoots coming up from the soil where you planted your seed. If you don’t see any sprouts, you may have planted bad seeds that weren’t able to germinate.^{[11]
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- Don’t worry if your seeds were bad because you can immediately dig it up and plant a new seed in its place. Just be sure to water the soil again once you plant your new seed.

Part 2

Part 2 of 3:

Caring for Your Plants

1
Water the soil once a week when it feels dry to the touch. Push your finger 2 inches (5.1 cm) into the soil and if it feels dry, it’s time to water. Use your watering can to slowly pour the water directly onto the soil. Allow the water to seep into the soil and watch for it to drain out of the bottom of the pot. If you don’t see any water coming out yet, add a little more water to the pot.^{[12]
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- If the soil still feels wet, avoid watering since you could make your seeds rot.
- Be careful not to pour the water too quickly since it could overflow from the top of the pot.
2
Remove dead or diseased leaves with hand pruners. While nasturtiums are pretty resilient, they can develop some diseases, such as powdery mildew. Check your plant occasionally for any leaves that are yellow and brown, as well as ones covered in a powdery white substance. Place your hand pruners at the base of the leave and cut them off to keep your nasturtiums healthy.^{[13]
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- Avoid putting diseased leaves into a compost bin since you could spread the bacteria. Throw them in with your regular trash instead.
3
Prune the nasturtium back once or twice during the growing season. Nasturtiums grow quickly and will spill over the edge of the pot if you leave it alone. Start trimming your nasturtiums within 1–2 months of planting them with a pair of hand pruners. Look for leggy vines or stalks and trim up to a third off their length. Shape your nasturtiums so they fit in the pot without falling out.^{[14]
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- Some varieties of nasturtiums don’t grow as quickly as others, so you may not have to prune them until later in the growing season.
Tip: Since nasturtiums are annual flowers, they’ll die at the end of the growing season so you won’t have to prune them then.
4
Pinch off dead or faded flowers to help prolong blooming. Within 1–2 months, your nasturtiums will start blooming beautiful flowers. If you plan on leaving the flowers on your plant, keep them until they start turning brown or drying out. Pinch the base of the flower with your fingers and carefully twist them off the stem. If you remove the flowers as they die, you may notice more blooms later in the growing season.^{[15]
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Part 3

Part 3 of 3:

Harvesting Nasturtiums

1
Start harvesting your nasturtium as the flowers start to bloom. While you can leave the flowers on your nasturtiums, they also have a spicy flavor that works great in a lot of dishes. Usually, your blooms will first appear within 1–2 months, so you can begin harvesting them as soon as they open.^{[16]
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Variation: If you only plan on using nasturtium leaves, you can start harvesting them as soon as your plant is 6 inches (15 cm) tall.^{[17]
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2
Snip or pinch off leaves and flowers when you want to eat them. Look for flowers and leaves that don’t have any damage or discoloration. Pinch where the leaf or flower connects to the stem and pinch it tightly between your fingers. Twist the lead or flower until it pops off. Leave at least ⅔ of the plant in the pot so it can regrow.^{[18]
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- You can also use hand pruners to cut the leaves or flowers off if you have trouble pinching them.
- Taste a single leaf or flower to make sure you enjoy the flavor before harvesting a lot from your plant.
3
Incorporate the nasturtium into meals for a peppery flavor. You can add the nasturtium leaves to any meal where you would normally use leafy greens. Try using them on top of a sandwich or incorporating them into your salads for a little bit of spice. Since the flowers are also edible, use them as a delicious, colorful garnish on salads or sandwiches to make them pop and add a burst of fresh flavor.^{[19]
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- Try using blueberries or raspberries in a salad with nasturtium greens and flowers if you want a sweet and spicy appetizer.
4
Collect and store the seeds once they fall off to replant next year. Nasturtiums die off at the end of the growing season, but luckily they produce a lot of seeds so you can grow them again right away. Look for the seeds on the stems near the flowers and leave them attached to the plant. As the plant ages and the seeds fall off, collect and store them in an envelope in a cool, dry place until you want to plant more nasturtiums.^{[20]
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- You can also crush the dried seeds if you want to add a pepper-like spice to meals, oils, or condiments.

Warnings

Nasturtium doesn’t grow well in soil with a lot of nitrogen, so avoid using high-nitrogen fertilizers.^{[21]
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You can injure nasturtium easily if you try and transplant it later on. Be sure to plant your seeds in the pot that’s large enough for it.^{[22]
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