How to Grow Parsnips

Quick Facts

Factor	Value
Soil pH	6 - 6.8
Germination temp	12°C
Optimal growing temp	15-21°C
Minimum survivable temp	-5°C
Time to harvest	100-120 days
Soil texture	RHS: "deep, light soil that drains readily"; avoid "stony or compacted soil", which causes forked roots.
Drainage	RHS: soil that "drains readily", in an "open, sunny area". Utah State: "sunny locations".
Edible parts	roots

At a Glance

When to Sow, Wherever You Garden

Sow parsnip seed direct once the soil has warmed to around 12°C (54°F). There's no fixed calendar month that works everywhere, since that temperature arrives at very different times depending on your climate. Seedlings can take 14 to 30 days to appear, depending on conditions, so a thin-looking row early on usually isn't a failure (RHS).

The roots are very hardy and can be left in the ground into winter and lifted as needed, and waiting until after the first heavy frost intensifies their sweetness and flavour (RHS).

Growth Stages

Stage	BBCH	Notes
Sowing & germination	0	Make a shallow 1cm-deep drill, sow thinly or three seeds at 15cm intervals, rows 30cm apart. Notoriously slow and erratic to germinate, needing soil around 12°C -- a mid-spring sowing succeeds far more reliably than an early-spring one on cold ground. RHS.
Thinning	3	Thin to one seedling every 15cm, removing the smaller, weaker ones. RHS.
Root development	4	The long, tapering root develops through summer and into autumn -- a slow-growing crop that spends the whole season bulking up rather than maturing quickly. RHS.
Harvest (after frost)	8	Best left until after the first heavy frost, which intensifies sweetness and flavour by converting starches to sugars. Ease roots out intact with a fork; they can be left in the ground through winter and lifted as needed. RHS.

Soil & Growing Conditions

Water: RHS: water "during dry spells" and keep the soil "evenly moist" to prevent root splitting. Utah State: "1-2 inches per week depending on weather", applied "frequent and uniform".

Soil pH range

6 6.8

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Harvest & Storage

When to pick: RHS: lift once "leaves start to die down in late summer or autumn", and flavour improves "after the first heavy frost". Utah State: harvest "when the roots reach full size".

Storage

RHS: parsnips "can be left in the ground into winter and harvested as required". Utah State: store at "32ºF and 95% relative humidity for two to four weeks".

Diseases

Downy mildew (general)

RHS names parsnips among the vegetables affected by downy mildews.

Pests

Stem and bulb nematode

Ditylenchus dipsaci

RHS names parsnips among affected vegetables, showing "crown and leaf base swelling, rotting, and splitting".

Carrot fly

Psila rosae

RHS: carrot fly affects "Carrot, parsnip, parsley, celeriac and celery".

Sources

1. FAO EcoCrop - Pastinaca sativa data sheet

These source is specific to this region. The full list of 6 sources behind this guide (FAO EcoCrop, Royal Horticultural Society, Utah State University Extension) is in the references of our UK guide to parsnips; they describe the plant itself, which is the same wherever it grows.