Fertilizer for Brussels Sprouts: NPK Guide and Application Rates
Brussels sprouts are long-season brassicas that take 80-100 days from transplant to harvest. They are heavy nitrogen feeders that need consistent nutrition throughout their extended growing period. Like cabbage, the stalk and leaf mass built during vegetative growth directly determines sprout size.
Quick Reference
What NPK Ratio is Best for Brussels Sprouts?
The recommended NPK ratio for brussels sprouts is 10-10-10. A balanced 10-10-10 feeds all three macronutrients equally, which works well when soil tests show no single deficiency.
Brussels Sprouts NPK needs shift at each growth stage. Balanced feed for transplant establishment during the Seedling phase, then balanced feed as sprouts begin to form along the stalk once flowering begins.
NPK by Growth Stage for Brussels Sprouts
| Growth Stage | NPK Ratio | Notes |
|---|---|---|
| Seedling | 10N 10P 10K N 10% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Balanced feed for transplant establishment |
| Vegetative | 20N 10P 10K N 20% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Heavy nitrogen for tall stalk and leaf growth |
| Flowering | 10N 10P 10K N 10% Nitrogen: leaf and stem growth P 10% Phosphorus: roots and flowers K 10% Potassium: health and disease resistance Learn more about NPK | Balanced feed as sprouts begin to form along the stalk |
| Fruiting | 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 | Reduce nitrogen once sprouts are sizing up |
When Should You Fertilize Brussels Sprouts?
In zone 3, start fertilizing brussels sprouts in May. In zone 9, begin as early as February. Apply every 3 weeks through the growing season.
Which Zones Can Grow Brussels Sprouts?
Brussels Sprouts grows in USDA zones 3 through 9, spanning a 7-zone range.
Fertilization Start by Zone
| Zone | Start Month |
|---|---|
| Zone 3 | May |
| Zone 4 | May |
| Zone 5 | April |
| Zone 6 | April |
| Zone 7 | March |
| Zone 8 | March |
| Zone 9 | February |
What Are the Best Fertilizer Products for Brussels Sprouts?
Look for products with an NPK close to 10-10-10. Espoma Garden-tone is the most popular choice among home gardeners for brussels sprouts.
- Espoma Garden-tone
- Miracle-Gro Performance Organics Edibles
- Neptune's Harvest Fish & Seaweed
Prices vary by retailer and region. Check current pricing before purchasing.
Container and Raised Bed Adjustments for Brussels Sprouts
Container Brussels sprouts need 7+ gallon pots and biweekly nitrogen-rich feeding; results are often inferior to in-ground growing
Common Fertilizing Mistakes with Brussels Sprouts
- Inadequate nitrogen results in spindly stalks with tiny, loose sprouts
- Not topping the plant leads to unevenly sized sprouts
- Hot weather above 80F causes loose, open sprouts regardless of fertilizer input
Tips for Fertilizing Brussels Sprouts
- Side-dress with nitrogen every 3 weeks from transplanting through early sprout formation
- Top the plant (cut off the growing tip) 3-4 weeks before first frost to force sprouts to mature evenly
- Frost improves Brussels sprout flavor; time planting for a late fall harvest
Organic Fertilizer Alternatives for Brussels Sprouts
Sources
Source:Clemson University ExtensionLast updated: