Brassicas ·Growing Guide
Forage Kale
Brassica oleracea var. acephala
Forage KaleBrassicasLow Maintenance
The highest-yielding brassica forage—Forage Kale produces more pounds of dry matter per acre than turnip, rape, or radish. Its exceptional cold hardiness (surviving well below 20°F) extends the grazing season deep into winter when every other annual forage is dead. Kale leaves and stems maintain 15-20% crude protein and high digestibil...
Shop Wicked Tuff Turf →Overview
About Forage Kale
Forage Kale (Brassica oleracea var. acephala) is the marathon runner of brassica forages. While turnips mature in 60-90 days and rape in 60-80 days, kale takes 90-150 days to reach full potential—but rewards that patience with the highest total yield and the longest grazing window of any annual brassica.
Kale's cold hardiness is its defining advantage. After frost kills turnip tops and rape leaves, kale continues to stand green and palatable. Repeated freezing and thawing actually improves kale palatability by converting starches to sugars. In many northern operations, kale provides grazing into December or January—months after grass, turnips, and other forages have finished.
Yield potential on fertile soil is remarkable: 4-8 tons of dry matter per acre, rivaling corn silage on a per-acre basis. This makes kale the most efficient brassica for converting fertility into livestock feed.
Kale requires more fertility and a longer growing season than other brassicas. It's not a quick-fix cover crop—it's a planned forage investment that pays off in late-season grazing value.
Kale's cold hardiness is its defining advantage. After frost kills turnip tops and rape leaves, kale continues to stand green and palatable. Repeated freezing and thawing actually improves kale palatability by converting starches to sugars. In many northern operations, kale provides grazing into December or January—months after grass, turnips, and other forages have finished.
Yield potential on fertile soil is remarkable: 4-8 tons of dry matter per acre, rivaling corn silage on a per-acre basis. This makes kale the most efficient brassica for converting fertility into livestock feed.
Kale requires more fertility and a longer growing season than other brassicas. It's not a quick-fix cover crop—it's a planned forage investment that pays off in late-season grazing value.
Fit
Where It Shines
Best for
- Late-season and winter livestock grazing
- Maximum brassica forage yield per acre
- Extending grazing season into December-January
- Dairy and beef cattle finishing forage
- Deer food plots that provide standing winter forage
- Silvopasture winter grazing supplements
- Operations with long growing seasons (120+ days frost-free)
Not ideal for
- Short-season plantings (needs 90-120 days minimum)
- Low-fertility soils (kale demands nitrogen)
- Lawns or turf
- Quick cover cropping (use mustard or radish instead)
- Biofumigation (lower glucosinolate than mustard)
- Dry conditions without supplemental moisture
From Seed to Stand
Establishment & Growth
Germination
Days 3-5: First seedlings emerge. Days 5-10: True leaves develop. Moderate establishment speed for a brassica. Slower to reach maturity than turnip or rape.
Growth Habit
Annual to biennial. Tall, upright stems 3-5 feet with large leafy canopy. Does not produce a bulb—all forage value is in the leaves and stems. Extremely high biomass producer.
Establishment Timeline
Emergence: 3-5 days. Grazeable: 90-120 days. Full biomass: 120-150 days. Persists through multiple hard frosts into winter.
Rates & Care
Seeding & Maintenance
| Seeding rate (new) | 3-5 lbs per acre; 0.1 lbs per 1,000 sq ft |
|---|---|
| Overseeding rate | Not typically overseeded |
| Soil temp to germinate | 40-45°F |
| Mowing height | Not mowed; grazed or harvested by hand/machine |
| Minimum mow height | Not applicable |
| First mow | Graze when plants reach 18-24 inches (typically 90-120 days from planting) |
| Soil pH | 6.0-7.5 |
| Soil preference | Fertile, well-drained loam. Kale rewards good soil with dramatically higher yields than on poor ground. Responds strongly to fertility. |
| Nitrogen needs | 80-120 lbs N per acre (heaviest nitrogen user among brassica cover crops) |
Conditions
Tolerances
SunFull sun (6-8+ hours)
ShadePoor to Moderate
DroughtModerate (deep taproot helps access moisture)
TrafficLow
ColdExcellent (the most cold-hardy brassica—survives well below 20°F; foliage quality improves after repeated frost)
HeatModerate (performs best in cool conditions)
Hardiness ZonesAnnual/biennial in all zones
Step by Step
How to Sow
1
Step 1: Prep
Plant 120-150 days before frost; apply 80-120 lbs N
2
Step 2: Fertilize
Scout for flea beetles at emergence
3
Step 3: Sow
Broadcast or drill at 3-5 lbs per acre
4
Step 4: Contact
Plant 1/4 to 1/2" deep; firm seedbed
5
Step 5: Water
Weed control important in first 6 weeks
6
Step 6: Mow/Establish
Graze at 18-24"; strip-graze into winter
Feeding & Timing
Fertilizing & Season
Fertilizer Recommendation
Apply 80-120 lbs N per acre—kale is the heaviest nitrogen feeder among brassica forages. Split applications (at planting and 4-6 weeks later) optimize uptake. Phosphorus and potassium based on soil test. Sulfur application (10-20 lbs S per acre) benefits brassica growth. Recommended: Wicked Growth commercial fertilizer program.
Find the right Wicked fertilizer →Seasonal Planting
Spring/early summer planting (May-June) in zones 4-6 to allow 120+ day growing season. Earlier planting gives higher yields. Late summer planting (July-August) possible but reduces yield significantly. Kale's long maturity requirement means it must be part of seasonal planning, not a last-minute decision.
In Context
How It Compares
Kale vs. Turnip: Kale yields more total forage and is more cold-hardy; Turnip matures faster and provides the bonus of edible bulbs. Kale vs. Rape: Kale yields more and survives colder; Rape establishes faster and is grazeable sooner. Kale vs. Radish: Completely different roles—Kale is for forage, Radish is for compaction breaking. Kale is the best brassica when maximum late-season forage yield is the goal.
Answers
Frequently Asked Questions
What is forage kale and how is it different from garden kale?
Forage kale (Brassica oleracea) is a tall-growing brassica bred for maximum livestock feed production rather than human culinary use. Forage varieties grow 3-5 feet tall and produce 5-10 tons of fresh biomass per acre—far more than garden kale varieties. While technically edible, forage kale is tougher, coarser, and less flavorful than culinary varieties. Its value is as high-yield, high-protein (15-20% crude protein) livestock feed for fall and winter grazing.
When should I plant forage kale?
Plant forage kale in late spring to mid-summer (May-July) for fall and winter grazing. Kale requires 90-150 days to reach full maturity, so planting timing depends on your first frost date and desired grazing window. For zones 4-6, plant by mid-June for October-December grazing. Kale germinates in 5-10 days at soil temperatures above 45°F and grows best in cool weather, producing maximum biomass during the fall cool-down.
What is the seeding rate for forage kale?
Seed forage kale at 3-5 lbs per acre broadcast, or 1.5-3 lbs per acre drilled in rows. For small plots, use approximately 0.1 lbs (1.5 oz) per 1,000 sq ft. Kale has very small seed—plant 0.25-0.5 inches deep in a firm seedbed. When included in brassica blends with turnips, rape, or radish, reduce kale to 1-2 lbs per acre. Kale benefits from 12-18 inch row spacing when drilled for maximum stem development.
How cold-hardy is forage kale?
Forage kale is the most cold-tolerant brassica forage, surviving temperatures as low as 10-15°F. In zones 5-7, kale provides grazing well into December-January, often outlasting turnips and rape by several weeks. Like turnips, frost improves palatability by converting starches to sugars. Kale stems may freeze but the leaves remain grazeable until repeated hard freezes destroy tissue. In mild winters (zones 7-8), kale can provide forage through February.
How much forage does kale produce per acre?
Forage kale produces 5-10 tons of fresh biomass per acre (1-2 tons dry matter), making it one of the highest-yielding brassica forages. Crude protein content ranges from 15-20% in leaves and 10-12% in stems. A well-managed kale crop can provide 100-150 grazing days per acre for a single cow. Kale consistently outyields turnips and rape in total biomass, though turnips provide more root-based energy.
Can deer eat forage kale in food plots?
Yes—deer readily browse forage kale, particularly the leaves. Kale's extended growing season and cold hardiness make it valuable in food plots for providing green forage through late fall and winter when most other food plot crops have frozen. Deer preference for kale increases after frost. Plant kale in combination with turnips, rape, or radish for a diverse brassica food plot that provides forage from September through January.
What nutrients does forage kale need to grow well?
Forage kale is a heavy feeder requiring 100-150 lbs nitrogen, 40-60 lbs phosphorus (P2O5), and 80-120 lbs potassium (K2O) per acre for maximum production. Boron is critical—apply 1-2 lbs per acre to prevent hollow stem. Kale responds strongly to nitrogen, with each 30 lbs N producing approximately 1 additional ton of fresh biomass. Soil pH of 5.8-7.0 is preferred. A soil test 2-3 months before planting ensures proper fertility planning.
