How to grow parsnip
Family Apiaceae. Hardy to USDA hardiness zone 3a+ (U.S. Department of Agriculture). Full sun. Ready in 100-130 days.
Sun
Full sun
Spacing
3-4 in
Days to harvest
100-130 days
Hardiness
Zone 3a+
What growers actually recorded
Loading zone 7b results…
When to plant parsnip
- Direct sow: ~-3 weeks after last frost.
Companion plants for parsnip
Plant with: Onion, Pea, Radish.
Avoid near: Carrot (competes for the same root zone and pests).
Common pests & problems
Carrot rust fly, armyworm.
Feeding & fertilizer
N-P-K ratio: Low N, higher P (3-6-6)
Organic options: Compost only in bed prep · Bone meal at sowing · Skip nitrogen top-dress
When to feed: Feed the bed, not the plant. Carrots/parsnips fork or hair-root with fresh manure.
Watch for: Forked roots = too much N or fresh manure; use only well-aged compost.
N = nitrogen (leaves), P = phosphorus (roots and flowers), K = potassium (fruit and disease resistance). How to read a fertilizer label →
Grower's tip
Seed loses viability fast: buy fresh each year. Leave roots in the ground through a hard frost; the cold converts starch to sugar.
When to plant parsnip in your zone
Free month-by-month sowing and transplanting lists, built from frost dates for your USDA (United States Department of Agriculture) hardiness zone.
Soil & water for parsnip
Soil & pH
6.0-6.8
Deep, loose, stone-free sandy loam, worked at least 12-15 in down. Parsnips grow a single long taproot and fork badly in rocky or compacted ground.
Use only well-finished compost from a prior season; fresh manure or high nitrogen causes forking and hairy side roots, same as carrots.
Watering
1 in / week; keep the top 1 in moist for the first 14 days
Fine sprinkle until germination, then deep drip. A burlap or board cover for the first 10 days keeps seed from drying out.
Carrots and parsnips crack when a dry spell is followed by a big soak. Keep the top 2 inches of soil just slightly damp for the whole season, not bone-dry then flooded.
Knowing when to harvest
- Roots reach 1.5-2 in shoulder diameter, typically 100-120 days from seeding.
- Flavor and sweetness improve markedly after one or more hard frosts, which convert starches to sugars; many growers wait deliberately for this.
- Can be left in the ground all winter under heavy mulch in zone 6 and colder, and dug through the dormant season.
- Foliage dies back but the root stays sound underground; dig before the ground fully freezes solid or the crop is inaccessible.
Storing & keeping
Store like carrots: cool (32-38°F), high humidity, packed in damp sand, for 4-6 months, or leave in situ under 8-12 in of mulch and dig as needed through winter.
What to expect
Per plant: 1 root, 6-14 oz depending on variety and season length
Per sq ft: 9-12 roots per sq ft in blocks
Troubleshooting parsnip
Skin irritation, blistering rash after handling foliage
Likely cause: Parsnip leaves and stems contain furanocoumarins that cause phytophotodermatitis on skin exposed to sunlight after contact
What to do: Wear gloves and long sleeves when weeding or harvesting parsnip tops, especially on sunny days; wash exposed skin promptly if contact occurs.
Forked or hairy roots
Likely cause: Rocky, compacted, or recently manured soil
What to do: Deep-till or double-dig the bed before sowing; use only aged compost.
Poor or spotty germination
Likely cause: Parsnip seed loses viability fast, often unusable after one year of storage
What to do: Buy fresh seed every season rather than relying on saved packets; sow generously and thin, since even fresh seed germinates unevenly over 2-4 weeks.
Varieties worth growing
Harris Model
Smooth, uniform roots and widely available; a dependable standard.
Hollow Crown
An old, reliable heirloom with good flavor after frost.
Javelin
Faster-maturing hybrid, useful in shorter-season gardens.
Growing parsnip in containers
Poor container crop given the 15 in taproot depth requirement; if attempted, use a fabric root pouch at least 18 in deep with loose, stone-free mix.
Nutrition
Beta-carotene, vitamin K, luteolin (parsley). A nutrient bargain per square foot.
Common questions
Why does everyone say to wait until after frost to dig parsnips?
Cold triggers the root to convert starch to sugar as a natural antifreeze response, which measurably sweetens the flavor. Digging before frost gives a blander, starchier root.
Can I use last year's leftover parsnip seed?
Not reliably. Parsnip seed viability drops sharply after about a year in storage, so germination from old seed is often poor even when stored well.
Where these numbers come from
- USDA Plant Hardiness Zone Map (2023 revision). Zone assignment and the 30-year normals behind every cold-hardiness figure.
- NOAA NCEI 1991-2020 Climate Normals. Frost dates, growing-season length, and the probability bands on both.
- Cornell, UMN, and UC Davis Cooperative Extension crop guides. Spacing, days to maturity, soil pH targets, and per-plant yield ranges.
- USDA FSIS / FDA Produce Safety guidance. Wash, cure, and cold-storage handling numbers.
Ranges are regional guidance, not a promise for your yard. Your own logged results always override the published range.