Fertilizer for Parsnips: NPK Guide and Application Rates
Parsnips are a long-season root crop (100-120 days) that become remarkably sweet after exposure to frost. Like carrots, they require low-nitrogen fertilization and deeply worked, stone-free soil for straight, well-formed roots. Fresh manure and high nitrogen cause forking and hairy roots.
Quick Reference
What NPK Ratio is Best for Parsnips?
The recommended NPK ratio for parsnips is 5-10-10. The phosphorus-heavy 5-10-10 ratio supports strong root systems and flower/fruit production in parsnips.
Parsnips NPK needs shift at each growth stage. Low nitrogen to encourage straight root growth during the Seedling phase, then not applicable; parsnips are harvested as a root crop once flowering begins.
NPK by Growth Stage for Parsnips
| Growth Stage | NPK Ratio | Notes |
|---|---|---|
| Seedling | 5N 10P 10K N 5% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Low nitrogen to encourage straight root growth |
| Vegetative | 5N 10P 10K N 5% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Phosphorus and potassium for long root development |
| Flowering | 5N 10P 10K N 5% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Not applicable; parsnips are harvested as a root crop |
| Fruiting | 0N 10P 10K N 0% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | P-K only for root sizing in the final month |
When Should You Fertilize Parsnips?
In zone 3, start fertilizing parsnips in May. In zone 9, begin as early as February. Apply every 6 weeks through the growing season.
Which Zones Can Grow Parsnips?
Parsnips grows in USDA zones 3 through 9, spanning a 7-zone range.
Fertilization Start by Zone
| Zone | Start Month |
|---|---|
| Zone 3 | May |
| Zone 4 | April |
| Zone 5 | April |
| Zone 6 | March |
| Zone 7 | March |
| Zone 8 | February |
| Zone 9 | February |
What Are the Best Fertilizer Products for Parsnips?
Look for products with an NPK close to 5-10-10. Espoma Garden-tone is the most popular choice among home gardeners for parsnips.
- Espoma Garden-tone
- Dr. Earth Root Zone
- Down to Earth Bio-Fish
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Parsnips
Container parsnips need 14+ inch deep pots filled with loose, stone-free potting mix; feed lightly at planting only
Common Fertilizing Mistakes with Parsnips
- Fresh manure or high nitrogen causes forked, hairy, misshapen roots
- Using old seed results in poor germination; always buy fresh parsnip seed
- Shallow or rocky soil causes stunted, forked roots regardless of fertilizer
Tips for Fertilizing Parsnips
- Work soil 12-14 inches deep and remove all stones before planting for straight roots
- Use fresh seed each year; parsnip seed viability drops dramatically after one season
- Leave parsnips in the ground through several frosts for maximum sweetness
Organic Fertilizer Alternatives for Parsnips
Sources
Source:Clemson University ExtensionLast updated: