Collards (Brassica oleracea)
Collards are a cool-season crop best suited for early spring or fall planting. Mature plants are hardy and can tolerate frost and light to moderate freezes. This leafy green is a staple in the South and is gaining popularity as a delicacy in Northern states. Rich in vitamins and minerals, collards are both nutritious and versatile.
Soil
Collards can thrive in a range of soil types but perform best in well-drained soils rich in organic matter, with a pH between 6.0 and 6.5. For maximum yields, heavier loamy soils are ideal, while lighter, sandy soils are better suited for early spring crops due to their excellent drainage.
Temperature
Maintain soil temperatures above 75°F for germination, then lower the air temperature to around 60°F. Collards grow best in cooler conditions, with an ideal temperature range of 55–75°F and an optimum range of 60–70°F. However, they can still produce quality crops in warmer summer climates.
Planting
Plant collards from early spring to about three months before the anticipated fall frost. For bunching, sow 3–4 seeds every 12–18 inches, ½ inch deep, in rows spaced 18–36 inches apart, and thin to one plant per cluster. For baby leaf production, sow 60 seeds per foot in a 2–4 inch wide band at a depth of ¼–½ inch.
Early Spring Crop
Sow 2 seeds per cell in 50- to 72-cell plug flats, 3–4 seeds per inch in 20-row flats, or directly in outdoor beds at a depth of ¼ inch. Seedlings are typically ready for transplanting within 4–6 weeks. Transplant seedlings outdoors, spacing them 12–18 inches apart in rows 18–36 inches apart.
Fall Crop
Begin seedlings in May and transplant them to the garden between June and July. In regions with early fall freezes, start the crop early to allow sufficient time for the heads to mature.
Winter Crop
Collards can thrive as a winter crop in areas with mild winters, where temperatures rarely drop below 32°F. In these regions, transplants can be planted anytime from September to February.
Spacing
Average spacing 8–15” in row and 18–36” between rows. For half-grown plants, space them 10 to 15 inches apart. For fully mature plants, increase spacing to 15 to 18 inches. If harvesting young collard plants like mustard greens, sow seeds closer together, with plants spaced 2 to 4 inches apart. In conventional systems, rows should be spaced 36 to 42 inches apart. Alternatively, multi-row beds with 2 to 4 rows on 38- to 60-inch centers can enhance yield and quality. In this setup, rows within each bed are spaced 12 to 18 inches apart.
Harvest
- Young Plants: Harvest entire plants while they are very young, similar to mustard greens, when spaced 2–4 inches apart.
- Half-Grown Plants: Harvest entire plants at the half-grown stage, spaced 10–15 inches apart.
- Fully Grown Plants: Harvest entire plants at full maturity, spaced 15–18 inches apart.
- Tender Leaves: Pick tender leaves from mature plants. These are typically bundled into 1- or 2-pound bunches for the market.
Before harvesting, consult with buyers to determine their preferred packaging requirements. Local sales often allow for bulk packaging, while shipments to distant markets or supermarkets typically require packing in crates or cartons. To maintain quality, icing may be necessary, especially for longer transport.
For more information, please see links below:
Note: This information is summarized. Additional details and expanded guidelines can be found in our production sheets available in the Holmes Seed Grower's Guidebook.
Downloadable Copy: