Parsnips Spacing Guide: Row Spacing, Thinning, and Root Development

Proper spacing is one of the most important steps in growing long, straight, high-quality parsnip roots. After more than 30 years growing root crops in Sonoma Valley—using narrow beds, careful thinning, and deep, loose soil—I’ve found that spacing alone can make the difference between forked, stubby parsnips and full-length, beautifully tapered roots.

Below is a complete guide to row spacing, seed spacing, and thinning so your parsnips have the room they need to size up.

Table of Contents

Why Spacing Matters for Parsnips

Parsnips elongate slowly over many months and send a taproot deep into the soil. When seedlings are crowded:

Roots compete for nutrients and moisture
Crowding pushes roots sideways or into each other
Airflow around foliage is reduced, increasing disease risk
Harvest size is significantly reduced

Generous spacing ensures that each root develops its classic, long wedge shape.

Row Spacing for Parsnips

Over the years I’ve trialed various spacings in raised beds and wide, shallow rows. These are the distances that consistently give me the best yields:

Row spacing: 12 to 18 inches
This allows enough room for foliage while still maximizing bed production.
In narrow beds (my usual setup), I plant dual rows 10–12 inches apart down the center of the bed.
In mounded or flat rows, use a single row with 18 inches between rows.

Seed Spacing: Starting Close, Then Thinning

Parsnip seed germination can be uneven—even with fresh seed—so I sow slightly heavy and then thin.

Sow seeds 1 inch apart in the row.
Cover lightly with ¼ inch of fine soil or sifted compost.
Keep moist and be patient; germination can take 14–21 days.

Sowing thickly ensures a full stand even with variable germination.

Thinning for Strong, Straight Roots

Thinning is crucial. If seedlings grow too close in the first weeks, the roots will twist and fork as they compete.

Here’s what I’ve learned through decades of growing:

First thinning: When seedlings reach 2 inches tall
- Thin to 2 inches apart.
Final thinning: When seedlings reach 4–5 inches tall
- Thin to 3–4 inches apart for full-size parsnips.
- If you prefer smaller, slimmer roots, thin to 2–3 inches apart.

I’ve found that the final spacing of 3–4 inches gives me the most reliable harvest of long, smooth roots.

Spacing Within Wide Beds

If you garden using the NEW method (narrow bed, equidistant planting, wide rows), which I rely on for most root crops:

Plant parsnips equidistantly at 3–4 inches apart in all directions.
This creates an even canopy and uniform moisture pattern, helping roots grow straight down.

This method has given me some of my straightest parsnips.

How Spacing Affects Root Shape and Quality

With consistent spacing and thinning, you can expect:

Long, straight taproots
Smooth shoulders
Minimal forking or branching
More uniform harvests
Better storage quality

Crowding, on the other hand, almost always leads to shorter, tangled, or deformed roots.

Final Tips From My Garden

Don’t delay thinning. The sooner each root has its own space, the better it forms.
Water deeply. Wide spacing encourages deep rooting, but only if moisture is available.
Use a gentle hand. When thinning, lift extras rather than pulling aggressively to avoid disturbing nearby roots.
Mark the rows. Parsnip seedlings emerge slowly; markers prevent accidental weeding.