Parsnips don’t need heavy feeding, but they do need the right nutrients at the right time. After more than 30 years growing parsnips in raised beds, narrow beds, and mounded rows, I’ve learned that consistent soil fertility—not high fertility—produces the best long, straight roots.

Too much nitrogen creates leafy tops and forked roots. Too little organic matter produces tough, stunted roots. The goal is balance, and the best way to get there is with slow, natural soil nutrition.

Below is a complete guide to fertilizing parsnips from pre-planting to late-season growth.

Table of Contents

Start With Fertile, Well-Amended Soil

Before sowing parsnips, I focus on building soil rather than adding fertilizer.

Organic Matter Is the Foundation

Each season, I add:

1–2 inches of compost
A handful of aged manure—only well-rotted and never fresh
A scattering of worm castings, especially in raised beds

This improves soil structure, retains moisture, and feeds parsnips slowly over their long season.

Avoid heavy, fresh manures; they cause forking and excessive top growth.

Before Planting: Light, Balanced Nutrition

Parsnips prefer a soil that is fertile but not overly rich. What works best in my garden:

Add a balanced organic fertilizer, such as 5-5-5 or 4-4-4, at ½ rate of what you’d use for leafy crops.
Rake lightly into the top 3–4 inches of soil.

This gives seedlings access to steady nutrition without overwhelming them.

Early Growth (0–6 Weeks): Minimal Feeding

During germination and early seedling growth, parsnips don’t need additional fertilizer. Their small roots are sensitive to salts and high nitrogen.

My rule after decades of growing root crops:

If the soil is rich in compost, don’t feed at all during early growth.

Watering evenly and thinning properly matter more at this stage than feeding.

Mid-Season Feeding (6–12 Weeks): Gentle, Root-Friendly Nutrition

As soon as seedlings are thinned and roots begin to extend downward, parsnips benefit from a mild mid-season boost.

What I use:

1. Side-dressing with Compost

Apply a ½-inch layer of compost along the row.
Scratch it lightly into the soil surface.

2. Low-Nitrogen Organic Fertilizer

If growth seems slow or foliage pale, apply a low-nitrogen blend:

2-3-4
3-4-4
Or any organic fertilizer labeled for root crops.

Apply sparingly—about ½ cup per 10 feet of row.

High nitrogen at this stage can cause branching or hairy roots.

Late Season (12+ Weeks): Light Feeding Only if Needed

By mid to late season, most of the parsnip’s growth is underground. Overfeeding now doesn’t help—it can actually reduce quality.

My late-season practices:

Add a small handful of wood ash (where allowed) around each row if soil is acidic.
- Wood ash provides potassium, which improves root density and flavor.
Water thoroughly after any amendment.
Do not add high-nitrogen fertilizer this late.

Most years, I don’t feed parsnips at all after week 12 because compost carries them through.