Collard Greens (Brassica oleracea Acephala Group)
2 sources cited · Verified
The short answer
- Plant
- Early March to mid July
- Site
- 6+ hours of sun, soil pH 6–6.5
- Biggest risk
- Club root
In the UK, collard greens go in the ground early March to mid July.
Collard greens (Brassica oleracea Acephala Group) — biennial grown as an annual.
Timing is the decision that matters most in the UK: there are 4 separate regional sowing windows, ranging from early March in Southern England to early March in Scotland.
Core growing advice on this page is checked against named horticultural and university-extension sources — see References.
Regional Planting Calendar
| Region | Sow |
|---|---|
| Southern England | early March to mid July |
| Midlands | early March to mid July |
| Northern England | early March to mid July |
| Scotland | early March to mid July |
Southern England - detail & sources
NC State gives a two-window US pattern (early spring or midsummer) rather than UK-specific dates, so a spring-through-midsummer window spanning both is applied across all four sub-regions rather than inventing a north/south gradient the sources do not support.
Midlands - detail & sources
NC State gives a two-window US pattern (early spring or midsummer) rather than UK-specific dates, so a spring-through-midsummer window spanning both is applied across all four sub-regions rather than inventing a north/south gradient the sources do not support.
Northern England - detail & sources
NC State gives a two-window US pattern (early spring or midsummer) rather than UK-specific dates, so a spring-through-midsummer window spanning both is applied across all four sub-regions rather than inventing a north/south gradient the sources do not support.
Scotland - detail & sources
NC State gives a two-window US pattern (early spring or midsummer) rather than UK-specific dates, so a spring-through-midsummer window spanning both is applied across all four sub-regions rather than inventing a north/south gradient the sources do not support.
Quick Facts
| Factor | Value |
|---|---|
| Soil pH | 6 - 6.5 |
| Sunlight | 6-6 hours direct sun |
| Soil texture | well-drained, rich in organic matter; loam for best yields (NC State) |
| Drainage | well-drained |
| Lifecycle | biennial grown as an annual |
| Edible parts | leaves |
At a Glance
Soil & Growing Conditions
Water: moist but not saturated, especially during germination (NC State)
Soil pH range
Span reflects genuine variation between the cited authorities, not a single agreed figure.
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Sowing | 0 | Sow 1/2 to 3/4 inch deep in early spring or midsummer; keep the top 3/4 inch of soil moist but not saturated during germination (NC State). |
| Transplanting / thinning | 3 | Transplant or thin to spacing matching the intended harvest stage: 2-4in for young leaves, 10-15in for half-grown, 15-18in for full-grown plants (NC State). |
| Leaf growth | 4 | Cold-hardy and heat-tolerant, growing well across regions; needs ample nitrogen for deep green colour and tender growth (NC State, UMD Extension). |
| Harvest | 8 | Ready 60-80 days after sowing; harvest whole plants at any stage or pick individual leaves from mature plants -- flavour sweetens after frost (UMD Extension, NC State). |
Harvest & Storage
When to pick: Ready 60-80 days after sowing (UMD Extension). Cut whole young plants (which regrow), half-grown or full-grown plants, or harvest tender leaves individually from a mature plant (NC State). Flavour turns sweeter after a few frosts.
Diseases
Pests
Collard Greens, Leaf to Harvest
References
-
Cool-season crop thriving in early spring or fall. Sow seeds in early spring or midsummer; transplant in early spring or late summer. Plant seeds 1/2 to 3/4 inch deep, never deeper than 1 inch. Spacing varies by harvest maturity: young harvest 2-4in apart, half-grown harvest 10-15in apart, full-grown harvest 15-18in apart; optimal bed configuration two to four plants wide with 12-18in between beds. Soil pH 6.0-6.5, well-drained, rich in organic matter; loamy soils give greatest yields, sandy soils suit early spring crops; incorporate 2 inches of compost seven days before planting; needs ample nitrogen for deep green colour and tender growth. Mature plant tolerates frosts and light to medium freezes. Harvest: cut entire young plants (which regrow for multiple harvests), half-grown plants, full-grown plants, or harvest tender leaves individually from mature plants. Keep top 3/4 inch of soil moist but not saturated during germination. Notable NC-performing varieties: Vates, Carolina Improved Heading, Georgia Southern, Blue Max, Heavi Crop. Pests/diseases not addressed in this document.
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country=USA
2 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.
Frequently Asked Questions
When should I sow collard greens in the UK?
In Southern England, from early March. In Scotland, wait until early March. Treat these as a guide rather than a fixed date — the governing rule is to sow only once frost risk has passed and temperatures are reliably warm enough.
When do I sow collard greens?
Sow early March to mid July.
What soil pH do collard greens need?
A pH of about 6–6.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect collard greens?
Our data links 2 diseases and 4 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Most of the advice on this page comes down to timing and spacing — sowing at the right moment, rotating beds, and giving plants enough airflow. The UK Garden Planner lays your plot out month by month so those decisions are already made before the season starts.
Get the UK Garden Planner →Instant PDF download · Written for UK growing conditions
Last verified 2026-08-29
Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.