Fast Growing Seeds: What Sprouts in Days, Not Weeks

Radish, cress, beans and sunflowers germinate in 2 to 5 days. A table by germination time and days to harvest, for gardens and for children.

By Salma October 28, 2026 3 min read Save to Pinterest

Young seedlings crowded in a plastic propagation tray — Photo: AndreasGoellner, Pixabay Content License, via Pixabay

On this page

Fast seeds share three traits: large or thin-coated, sown shallow, into warm moist soil. Those three explain the whole table below.

The short answer

Cress and mustard germinate in one to three days, radish, rocket and pak choi in two to five, and beans, squash, sunflowers and courgettes in three to seven — all large or thin-coated seeds sown shallowly into warm moist soil. For seed to harvest, cress takes five to seven days, microgreens seven to fourteen, radish twenty-five to thirty, baby salad leaves twenty-five to thirty-five. For children, cress, sunflower, radish, beans and nasturtium all give a visible result within two to four weeks. Soil temperature matters more than soaking: most seeds germinate two to three times faster at their ideal temperature.

1–3 days: cress, mustard
2–5 days: radish, rocket, pak choi
3–7 days: beans, peas, squash, sunflower, courgette
Harvest fastest: cress 5–7 days, radish 25–30, salad leaves 25–35
Temperature beats soaking every time

Germination speed

seed	days to germinate
Cress	1–3
Mustard	2–4
Radish	2–5
Rocket / arugula	3–5
Pak choi	3–5
Beans (bush, runner)	4–7
Courgette / squash	4–7
Sunflower	4–7
Peas	5–8
Lettuce	5–10
Spinach	6–10
Nasturtium	7–12
Sweetcorn	7–10
Carrot	14–21
Parsley	21–28
Parsnip	21–28

Seed to harvest

crop	days to harvest
Cress on damp paper	5–7
Microgreens	7–14
Radish	25–30
Baby salad leaves	25–35
Rocket	30–40
Pak choi (baby)	30–45
Bush beans	50–60
Courgette	50–60
Spring onion	60
Nasturtium (flowers)	50–60
Calendula (flowers)	50–60

For children

seed	why it works
Cress	Days to germinate, a week to eat. Works on kitchen paper
Sunflower	Big seed, big result, measurable weekly
Radish	Sowing to pulling inside a month
Runner bean	Climbs fast enough to mark on a stick
Nasturtium	Reliable, and the flowers are edible

Warmth, not soaking, is the lever

Most seeds germinate two to three times faster at their ideal soil temperature than at a cool one. A heat mat, a propagator lid or simply waiting two weeks later in spring beats any pre-soaking trick — though large hard seeds such as beans and nasturtium do gain a day from eight hours in warm water.

Why fast seeds sometimes are not

Cold soil — the dominant factor for nearly everything
Sown too deep. A quarter inch too far down stops small seed
Surface dried out for a day mid-germination
Old seed. Most vegetable seed loses vigour after two to three years
Compacted or crusted surface, which seedlings cannot push through

Using them late in the season

Count back from your first frost date, add two weeks for slower autumn growth, and sow anything whose days-to-harvest fits: radish, rocket, cress, salad leaves, pak choi and spinach all make a crop in four to six weeks and fill the gaps as summer crops come out.

Common questions

What seeds germinate the fastest?

Cress and mustard in one to three days, radish, rocket and pak choi in two to five, beans, squash, sunflowers and courgettes in three to seven. All of those are large or thin-coated seeds sown shallowly into warm moist soil, which is the combination that produces fast germination. The slow end of the garden — parsley, carrots, celery, lavender, parsnip — all share the opposite traits: small, hard-coated and often needing a chill or light treatment.

What is the quickest thing to grow from seed to harvest?

Cress on damp kitchen paper in five to seven days, then microgreens in seven to fourteen, radish in twenty-five to thirty, baby salad leaves in twenty-five to thirty-five and spring onions in about sixty. Among flowers, nasturtium and calendula flower in roughly fifty to sixty days from sowing. For a garden that needs to produce something quickly — or a child who needs to see progress — radish and cress are the two that never disappoint.

What are the best fast seeds for children?

Cress, sunflower, radish, beans and nasturtium. Cress germinates in days on damp paper and can be eaten within a week; sunflower seeds are big enough for small fingers and grow visibly day by day; radish goes from sowing to pulling inside a month; runner beans climb fast enough to measure; and nasturtium flowers reliably and the flowers are edible. The common factor is a large seed and a visible result inside two to four weeks.

Does soaking seeds make them germinate faster?

For some, noticeably. Large hard-coated seeds — beans, peas, sweetcorn, nasturtium, squash — benefit from eight to twelve hours in plain warm water, which brings germination forward by a day or two. Very fine seeds do not need it and can be damaged. The far more important factor is temperature: most seeds germinate two to three times faster at their ideal soil temperature than at a cool one, which is why bottom heat beats every seed-soaking trick.

Why are my fast seeds taking ages?

Cold soil, sown too deep, or the surface drying out. Soil temperature is the dominant factor for nearly every species, and a tray on a cool windowsill can sit well below the room temperature; a quarter inch too deep is enough to delay or prevent emergence for small seeds; and a surface that dries for even a day during germination kills seed that has already started. Old seed is the fourth cause — most vegetable seed loses vigour noticeably after two to three years.

Can I sow fast seeds late in the season?

Yes, and it is one of the best uses for them. Radish, rocket, cress, baby salad leaves, pak choi and spinach all crop in four to six weeks, so a sowing in late summer or early autumn still produces a harvest before the first frosts, and they fill gaps as other crops come out. Count back from your first frost date, add two weeks of margin for cooler autumn growth, and sow anything whose days-to-harvest fits.

Backyard Weekly

Know what to plant, week by week

Join the weekly email for seasonal jobs, fixes for what is going wrong, and gear worth buying.

Not ready to subscribe? The planting calendar is free and needs no email.

By subscribing you agree to our privacy policy. Grow In Backyard will never sell your address.

A loose-leaf lettuce plant growing in bare soil

Growing Guides · Sep 1, 2026