How to Grow Parsnips: A Sweet Root the Frost Makes Sweeter

GardenDraft Team · July 20, 2026 · 5 min read

Part of: Garden Planning Guides · Planting Calendar & Frost Date Guides · How to Grow Vegetables — Crop Guides A–Z

Parsnips are a lesson in patience rewarded. This pale, sweet, nutty root looks like a cream-colored carrot and is grown much the same way, but it takes a long, slow season and, crucially, gets better the longer it stays in the cold ground. A frost or two turns its starches to sugar, so parsnips dug after the first hard freeze are among the sweetest things the garden produces. They ask for two things: fresh seed and patience.

Use fresh seed — this is the big one

The number-one reason parsnips fail is old seed. Parsnip seed loses its viability faster than almost any other vegetable (it's often nearly dead by its second year), so always buy fresh seed each season and don't try to save last year's packet. Even fresh, it germinates slowly and unevenly, taking two to three weeks, so keep the soil consistently moist through that long wait and don't give up early. Sowing a few radish seeds in the same row marks where the parsnips will come up and breaks any soil crust.

Loose, deep, stone-free soil

Like carrots, parsnips form a long taproot and need deep, loose, stone-free soil to grow straight and unforked. Rocky or compacted ground gives twisted, stubby roots. Work the bed deeply before sowing and skip fresh manure, which causes forking. Direct-sow (parsnips don't transplant) about half an inch deep in full sun, and once seedlings are up, thin them to about 3 to 4 inches apart so the roots have room to size up. Keep them evenly watered and otherwise leave them be — it's a long, hands-off season of around 100 to 120 days.

Let frost sweeten your parsnips

Here's the payoff for the long wait: parsnips are sweetest after cold. Leave them in the ground through fall and let a few hard frosts hit them, which converts their starch to sugar and deepens the flavor. In many climates you can keep digging them right through winter under a mulch of straw, lifting fresh roots as needed — the cold ground is the best storage there is. They'll even overwinter and resume growth in spring, though they turn woody and bolt once they do, so use them up before the weather warms.

Few pests, one caution

Parsnips are largely trouble-free, sharing the occasional carrot pest like the carrot rust fly. One safety note worth knowing: the foliage can cause a skin rash in sunlight for some people, so wear long sleeves if you're handling the tops on a bright day. Otherwise this is a plant-and-wait crop with a delicious reward. Plan its long season on the planting calendar.