Harvesting nasturtiums is simple, quick work — and it matters, because a nasturtium that is picked regularly flowers far longer than one left alone. These are cheerful, fast-growing annuals that bloom from early summer until frost, and every flower you cut or deadhead prompts the plant to make more. This guide covers when to harvest nasturtiums — the signs that tell you a bloom is ready, how to cut it without damaging the plant, the best time of day to cut, how to condition the stems, what happens if you leave blooms too long, how to deadhead, and how to save seed. The timing below uses the published range for this flower, 50–60 days to maturity, which varies by variety, climate and soil, so treat it as a guide and judge each plant by what you can see and feel.
Nasturtiums are a flower in the Tropaeolaceae family, with tender cold tolerance and moderate water needs. They need full sun and a soil pH of 6.0–7.5, and plants are spaced 8–12 inches apart. They are usually direct sow. Knowing those basics helps you judge harvest time, because a plant that has been watered evenly and grown in the right conditions produces long stems and large, bright flowers, while a stressed plant produces small flowers and more leaves than blooms. Keep a simple note of when you sowed and when you first cut — after one season you will have a record far more useful than any general guide. As with all the timings in this guide, these are broad published ranges, not exact dates for your garden, so check your local extension service for your area.
Nasturtiums at a glance
| Detail | Guidance |
|---|---|
| Days to maturity | 50–60 days |
| Family | Tropaeolaceae |
| Category | flower |
| Cold tolerance | tender |
| Water needs | moderate |
| Sun | full sun |
| Soil pH | 6.0–7.5 |
| Spacing | 8–12 inches |
| Sowing | direct sow |
If you are still growing this flower, the growing guide for nasturtiums covers soil, spacing, water and care in full, and the Zone 5 page for nasturtiums covers timing in a cold-winter climate. The harvest date calculator can help you work out roughly when a sowing should be ready, and the Zone 13 page for nasturtiums covers timing in a frost-free climate.
Signs that nasturtiums are ready to cut
The best harvest decisions are made with your eyes and hands, not with the calendar. Nasturtiums bloom over a long season, and the window for cutting is generous — but cutting at the right stage gives you the longest vase life. For nasturtiums, the signs are:
- Petals fully open and bright: The flower should be fully open with the petals flat and the colour bright and even for the variety. A bloom whose petals are curling at the edges or fading is past its best for cutting.
- A long, firm stem: Nasturtium stems are soft and hollow, so choose flowers on the longest, firmest stems you can find. A stem that bends easily and flops over will not stand up in a vase.
- Fresh centre: The centre of the flower should look fresh and clean. A centre that is going brown or shedding pollen has been open too long.
- New buds nearby: Look for the buds forming in the leaf joints below the open flower. Cutting just above one of those buds encourages it to grow into the next flower, which is how the plant keeps producing.
The single most useful habit is to check plants every day or two once flowering starts, and to cut a test stem if you are unsure. One test stem in a vase tells you more than a week of guessing. If it stays fresh for several days, cut the rest at the same stage. If it wilts within hours, the blooms were too young or the day was too hot — wait and cut in the cool morning instead. Over a season you will learn to read this flower at a glance, and harvesting will become quick and confident.
How to cut nasturtiums without damaging the plant
Use clean, sharp scissors, and cut in the cool of the morning when the stems are full of water. Choose a stem with a fully open flower, follow it down to a leaf joint where a side shoot or bud is forming, and cut just above that joint. That side shoot will grow into the next flowering stem, so cutting just above a joint is what keeps the plant branching and producing.
Cut stems as long as the plant allows — nasturtium stems are often shorter than other cut flowers, so take what you can get and use small vases or jam jars for arrangements. Put cut stems straight into a bucket of cool water, out of direct sun, and keep them there until you bring them indoors. Do not leave cut nasturtiums lying on hot soil or in a warm car, because their soft stems wilt very fast. Strip off any leaves that would sit below the waterline in the vase, since submerged leaves rot quickly and foul the water. Wash your hands and tools before handling, keep your tools clean between plants, and put cut stems in a clean bucket rather than on the soil, where they pick up dirt and pests.
Best time of day and how often to cut
Cut in the morning, after the dew has dried but before the heat of the day, when the stems are cool, crisp and full of water. Blooms cut in the heat of the day wilt fast and do not keep as well. Nasturtiums take 50–60 days to maturity, and a plant in full flower may produce new blooms every day for weeks, so check every day or two and cut a few stems at a time rather than taking everything at once.
Regular cutting is not just about getting the best vase life — it is how you keep the plant flowering. Nasturtiums respond to cutting by branching: every stem you remove prompts side shoots to grow, and each of those carries a flower. A plant that is never cut flowers for a shorter period and then runs to seed. A plant that is cut and deadheaded often can flower from early summer until the first frost. In a frost-free climate that can mean months of extra flowers from the same plants.
What happens if nasturtiums are left too long
Left too long, nasturtium blooms fade, drop their petals, and set seed. Once the plant has set a lot of seed, it slows down flowering and puts its energy into ripening that seed instead. Trailing types can also sprawl across paths and smother neighbouring plants if they are not kept in check, and spent flowers left in wet weather can develop mould that spreads to healthy foliage. A single bloom left past its best does not harm the plant, but a whole patch left uncut for weeks will flower less and look messier.
The cost of leaving blooms too long is a shorter flowering season and fewer flowers overall. Deadhead spent blooms promptly — covered below — and trim back trailing stems that are heading where you do not want them. A check every day or two during bloom season takes a few minutes and catches problems while they are still small. If you do find mouldy or rotting blooms, remove them promptly and put them in the bin rather than the compost, so disease does not carry over. Watch for aphids too, which love nasturtiums — the plant is often used as a trap crop, and a heavy aphid colony is a sign to check the rest of the garden.
Conditioning stems and vase care
Recut each stem at an angle just before placing it in the vase, to open the stem and help it take up water. Use a clean vase filled with cool water, and change the water every day or two, recutting the stems each time, since nasturtium stems are soft and foul the water quickly. Keep the vase out of direct sun and away from ripening fruit, which gives off a gas that speeds up ageing in cut flowers. Nasturtiums cut at the right stage usually last several days in a vase in a cool room, though they are shorter-lived than woody-stemmed flowers.
If a stem wilts badly in the first hours, it was probably cut in the heat or left out of water too long. Try recutting the stem and placing it in deep, cool water for a few hours in a cool room — some stems recover. Blooms cut too young, before the petals have fully opened, often stay half-open and fade quickly. The lesson is in the timing: cut fully open flowers in the cool morning, and get them into water immediately.
Deadheading nasturtiums to keep them flowering
Deadheading is the most important job with nasturtiums, and it is also the simplest. Once a flower fades, cut or pinch the spent bloom off just above the first leaf joint below it where a side shoot is forming. This stops the plant putting energy into seed and prompts it to branch and flower again. Do it every day or two while you are cutting for the vase — the two jobs are really the same job, and a few minutes with scissors is enough.
If you stop deadheading in late summer, the plant will set seed and start to wind down. That is fine if you want to save seed, covered below, but it means fewer flowers. Many gardeners deadhead hard through the season and then let a few flowers go to seed at the end, getting both a long flowering season and seed for next year. Nasturtiums are annuals, so the plant will die with the first frost — deadheading simply makes the most of the time it has. One more tip: nasturtiums flower best in poor soil. Rich soil and heavy feeding produce lush leaves and few flowers, so do not overfeed them.
Saving nasturtium seed
Nasturtium seed is one of the easiest to save. Let a few flowers go to seed at the end of the season — stop deadheading those stems and let the seed pods form. The seeds are large, round and green at first, turning pale and dry as they ripen. When they are dry and come away easily from the plant, collect them into a paper bag, spread them out to dry for a few days indoors, then store them in a labelled paper envelope in a cool, dry place.
Nasturtium seed usually comes fairly true to type, though mixed plantings may cross and produce surprises. Label any seed you store with the variety and the date, and use it within a year or two for the best germination. Sow it direct where it is to flower next year, since nasturtiums prefer not to be transplanted and dislike root disturbance.
Common harvesting mistakes
- Cutting blooms before they are fully open, so they fade without ever opening properly.
- Cutting in the heat of the day instead of the cool morning.
- Snapping soft stems instead of cutting just above a leaf joint, which leaves a ragged wound.
- Never deadheading, so the plant sets seed early and stops flowering.
- Overfeeding nasturtiums, which produces leaves at the expense of flowers.
- Leaving cut stems out of water, even for a few minutes, since soft stems wilt so fast.
Most harvesting mistakes come from the same place: guessing instead of looking, and leaving the garden alone at the critical moment. A short check every day or two, a cut just above a leaf joint, and cutting little and often will avoid nearly all of them.
Frequently asked questions
When are nasturtiums ready to cut?
When the petals are fully open, bright and flat, on a long firm stem. They take 50–60 days to maturity, but judge each bloom by how it looks, not the calendar.
Does cutting nasturtiums make more flowers grow?
Yes. Every stem you cut prompts side shoots to grow and flower, and deadheading stops the plant running to seed. Regular cutting can extend flowering until the first frost.
Why do my cut nasturtiums wilt so fast?
Their stems are soft and hollow, so they lose water quickly. Cut in the cool morning, put stems straight into cool water, and change the water every day or two.
Why does my nasturtium have lots of leaves and few flowers?
Usually because the soil is too rich or it has been fed too much. Nasturtiums flower best in poor soil — stop feeding and the flowers should follow.
How do I save nasturtium seed?
Let a few pods ripen until they are dry and pale, collect them into a paper bag, dry indoors, and store in a labelled envelope. Sow direct next year — check your local extension service for the best sowing windows in your area.
Related guides
For more harvesting help, browse the guides hub, plan your next sowing with the planting calendar, and try the harvest date calculator and the seed starting calculator. If you are growing in a frost-free climate, the Zone 13 page for nasturtiums and the growing guide for nasturtiums are the best next reads. And as always, check your local extension service — local advice beats any general guide for your soil, your weather and your varieties.