Growing Parsley: Slow Seed, Short Soaks and a Two-Year Life
Parsley seed is slow by nature. A day in water was the best plain-water soak in one trial, and another trial found no gain from soaking.
Parsley has a reputation for testing a gardener’s patience. You sow a row, water it faithfully, and for weeks nothing seems to happen. A common tip is to soak the seed first, sometimes for days.
Seed trials support a much shorter soak, or none. In a 2022 peer-reviewed study, a day in water came out best of the plain-water soaks, and longer soaks did no better and sometimes worse. Patience does most of the work, and once parsley is up it gives months of leaves, even from a spot in partial shade.
Why is parsley so slow to germinate?
It’s slow by family habit. Parsley belongs to the carrot family, the Apiaceae, and a peer-reviewed paper on a wild relative (Plant Biology, 2018) notes that “underdeveloped, linear embryos are a major feature of the Apiaceae.” In such seeds the embryo has to finish growing before a root emerges. The paper doesn’t test parsley itself.
The Royal Horticultural Society warns that parsley can be slow to germinate, “often taking a month or more, so don’t give up on them too soon.” Seedlings should appear within six weeks.
Does soaking parsley seed actually help?
A day’s soak came out best in one nursery trial, and the wider evidence is mixed.
- The 2022 trial. In a HortScience study, researchers soaked seed of the cultivars ‘Krausa’ and ‘Titan’ in water for 24, 48, 72 or 96 hours and assessed it for nursery seedling production. Compared with untreated seed, the 24-hour soak had the highest emergence speed and total emergence. Longer soaks lowered emergence speed, and total emergence generally fell. The paper’s summary doesn’t say whether seed was dried before sowing.
- The Oregon trial. A 2007 Oregon State University report, grown in trays of field soil or potting mix in a growth chamber, soaked seed for seven days in water or in priming solutions. In field soil, untreated seed reached 88% germination and no treatment beat it. Rubbing the seed coat with sandpaper before soaking made things worse.
Seed priming, where seed takes up a carefully measured amount of moisture, is a different process. A 2000 HortScience paper by Pill and Kilian on that method found that “All priming treatments stimulated and hastened germination.”
So soak for about a day if you like, or skip it. The RHS sowing advice doesn’t include soaking at all.
If your parsley never came up
- Timing. Sow outdoors after your last spring frost, as NC State Extension suggests, or start seed indoors before it. The RHS sows outside from mid-spring to late summer.
- Depth. Sow about 1 cm deep.
- Moisture. Don’t let the soil or compost dry out while you wait.
- Seed age. Kansas State University Extension lists parsley seed as good for one year, with the carrot family “usually good for only 1 to 2 years” even when stored cool and dry.
Flat-leaf or curly?
Grow flat-leaf for flavour and curly for looks. The RHS describes flat-leaved types as having “a stronger flavour” and curly types as more decorative, milder and usually shorter, and NC State calls the Italian flat-leaf variety the one with “the strongest and sweetest flavor.”
Both agree the taproot dislikes being moved. NC State finds parsley easier to start from young plants because germination is so long, and the RHS prefers sowing straight into the final spot, thinning to 15 to 30 cm apart, or into a pot at least 25 cm wide and deep.
Does parsley really grow in shade?
Partial shade suits it well. In the RHS guide it “will grow well in full sun or partial shade” in fertile, moisture-retentive soil, and pots can move into shade during hot, sunny spells. NC State adds that it grows better in cool summer areas and can wilt in the hot, humid US South. Our windowsill herbs guide covers growing herbs in pots indoors.
Take a few stems from the outside of each plant. Regular picking, the RHS notes, “encourages plants to produce more leaves.”
What happens in the second year?
Parsley is a biennial, so it makes leaves in year one and flowers in year two. Second-year plants “will stop producing tasty leaves and concentrate on flowering and setting seed instead,” according to the RHS, which is why most gardeners treat parsley as an annual. NC State notes the leaves are “not as flavorful when it flowers” and feel coarser.
The flowers are edible and attract butterflies, NC State says, and the RHS suggests keeping a couple of plants to collect seed for sowing. To avoid a gap, sow small batches every few weeks through the season, and cover outdoor plants with cloches or bring pots indoors to keep them producing through winter.
If seedlings pop up on their own, be sure of what you’re picking. NC State notes that the leaves of poison hemlock, a highly toxic weed in the same family, “resemble parsley.” Hemlock has white flowers and purple-spotted stems that smell foul when crushed, while parsley’s flowers are greenish-yellow.
Why are caterpillars eating my parsley?
In North America they’re most likely parsleyworms, the caterpillars of the eastern black swallowtail butterfly. NC State lists their food plants across the carrot family, including parsley, dill and fennel, and calls them “easily hand-picked.” Disturbed older ones push out a forked orange gland, the osmeterium, which smells unpleasant.
Penn State master gardeners suggest adding other host plants such as dill and fennel, which “allows gardeners to enjoy the harvest.” In Britain, the native swallowtail feeds solely on milk-parsley, a wild fen plant, rather than garden parsley.
What does a real portion of parsley contain?
A lot of vitamin K and modest amounts of most else. The USDA’s FoodData Central database entry “Parsley, fresh” gives values per 100 g, and its “10 sprigs” portion weighs 10 g. Here’s that portion against the US Daily Values.
- Vitamin K: 164 µg, about 137% of the Daily Value.
- Vitamin C: 13.3 mg, about 15%.
- Iron: 0.62 mg, about 3%.
That vitamin K matters for anyone taking warfarin. MedlinePlus advises people on the drug to “eat consistent amounts of vitamin K-containing food on a week-to-week basis” and says “Do not eat large amounts of leafy, green vegetables.” NC State rates the plant’s poison severity as low, noting that “large amounts are needed” to cause skin sensitivity to sunlight.
What this means for you
- Soak seed for a day at most, or skip it, then keep the soil moist and allow up to six weeks.
- Use fresh seed and sow about 1 cm deep where the plants will grow.
- Choose flat-leaf for flavour and curly for edging and looks.
- Give it partial shade in hot summers, and pick from the outside.
- Sow small batches every few weeks, and let a second-year plant flower if you want seed.
- Add host plants such as dill or fennel if swallowtail caterpillars visit, and check any self-sown seedlings carefully.
Have you ever soaked parsley seed, and did it come up any faster for you? Hit reply and tell us.
How we made this: AI tools helped us research and draft this post. We checked every figure, quote and link against its original source before publishing. Figures are as of 8 November 2026.
Grown with intention by Dynamic Nexus Garden.