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Vegetable Crop Calendars (A–C)Parsnip Planting Calendar
Parsnips ask for patience at both ends of the season. The seed takes weeks to emerge, and the roots reward you only after cold weather arrives.
Key points
- Sow two to three weeks before your last frost, once soil reaches about 40 degrees.
- Expect 14 to 21 days to emerge, so keep the seedbed moist and use fresh seed.
- Plan on roughly 100 to 120 days to mature, and let a few frosts sweeten the roots.
- Harvest overwintered roots before spring regrowth makes them woody.
When should you plant parsnips?
Utah State University Extension recommends planting about two to three weeks before your last spring frost, once the soil has reached 40 degrees. That is early, because parsnips need a long season and tolerate cool conditions.
Work out the date yourself: find your average last frost from your local weather service, count back two to three weeks, and confirm with a soil thermometer. For example, if your last frost usually falls around the end of April, you would be looking at early to mid April, subject to soil readings.
Some gardeners also mark the row with quick-germinating radish seed so they know where the slow parsnips will appear and avoid hoeing them out by accident.
Why are parsnips so slow to come up?
The same Utah source says seed germinates best at 55 to 65 degrees and takes 14 to 21 days to emerge. Soil above about 80 degrees reduces germination. So a warm spell is not an advantage here.
Keep the seedbed evenly damp through that whole stretch. A crust forming over the row is the usual reason for a poor stand, so some growers lay a board or burlap over the row and check daily, removing it as soon as sprouts show.
Some growers soak seed or pre-sprout it to speed the wait. Pre-sprouted seed is fragile, so sow it carefully and never let it dry out once it is in the ground. Whatever you try, fresh seed is the single biggest factor.
How far apart should you thin parsnips?
Utah State suggests rows 12 to 18 inches apart and thinning seedlings to about 3 to 6 inches. The page itself is not perfectly consistent on exact spacing, so treat that as a range and let your variety and soil guide you.
Sow generously because of the unreliable germination, then thin in two passes. Use scissors to cut weak seedlings rather than pulling, which can disturb the slim taproots of the plants you want to keep.
Weeds are a particular nuisance because parsnips are slow to establish. Shallow cultivation between rows while seedlings are small keeps competition down without harming roots.
How long until parsnips are ready?
Roots are usually mature 100 to 120 days after seeding according to Utah State. That is a long commitment, and it is why parsnips take up a bed for most of the season.
Because of that, plan what follows them. If your frost-free season is short, choose a quicker-maturing variety and sow at the early end of your window.
If your bed is needed again quickly, parsnips are probably not the right crop. They suit gardeners with a spot they can give up for most of a season.
Do frost and winter improve parsnip flavor?
Utah State reports that several weeks of cool, frosty weather improves flavor, and that temperatures down to 32 degrees do not seriously damage plants. Many gardeners wait for a few frosts before digging.
Roots can stay in the ground over winter and be harvested in early spring, when they are especially tender and sweet. Dig before new leaves emerge, because roots turn woody once the plant restarts growth. In very cold regions, mulch heavily so the ground stays workable.
What mistakes sink a parsnip crop?
Old seed is the first. Parsnip seed loses viability quickly, so buy fresh each year. The second is planting into compacted or stony soil, which gives forked roots. The third is letting the seedbed dry out.
Prepare loose, deep soil, remove stones, and follow a soil test for amendments. Wear gloves when handling foliage in sun, since parsnip sap can irritate skin in some people.
Pests such as carrot rust fly and canker can affect parsnips in some areas. Ask your county extension office for current identification and recommendations, and follow any label exactly.
How do you plan a parsnip bed from start to finish?
Because parsnips occupy ground for so long, a plan on paper saves frustration. Begin by choosing the bed in autumn, loosening it deeply and removing stones so roots can run straight.
Then follow this sequence through the season:
- Test soil and follow local recommendations for amendments.
- Sow fresh seed at the early end of your window, keeping the surface damp.
- Thin in two passes, first when seedlings are small and again when they crowd.
- Mulch after the ground begins to freeze to keep soil workable for winter digging.
- Harvest after several frosts, or in early spring before regrowth.
Timing at a glance
| Item | Window | Caveat |
|---|---|---|
| Parsnips, Utah State guidance | About two to three weeks before the last spring frost, once soil is 40 F | Relative to your own average last frost; Utah extension guidance, adjust locally. |
Sources and further reading
Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.