How to Grow Crimson Clovers USA | Planting & Establishment

Growth Stages

Stage	BBCH	Notes
Sowing	0	PFAF: pre-soak seed for 12 hours in warm water, then sow in spring to early summer in situ; alternatively, sow in early autumn for use as a winter green manure.
Establishment	3	RHS: generally pest-free and disease-free once established. PFAF: tolerates strong winds but not maritime exposure; fast-growing and weed-suppressing.
Flowering	6	RHS: dense, conical heads of red flowers appear from May to September, providing a good nectar source for bees.
Seed ripening and harvest	8	PFAF: seeds ripen through summer into autumn and can be sprouted for salads or dried and ground into flour; flower heads can also be picked and dried for tea.

Quick Facts

Factor	Value
Sunlight	6-8 hours direct sun
Minimum survivable temp	-10C
Drainage	Moist but well-drained or well-drained (both sources); PFAF: tolerates light, medium or heavy soils, even nutritionally poor ground.
Lifecycle	RHS: a slender, upright annual or short-lived perennial, rated H4 (-10 to -5C). PFAF corroborates independently: hardy to UK zone 4 and "not frost tender."
Edible parts	leaves, flowers, seeds

Harvest & Storage

When to pick: PFAF: harvest seed once ripe (July-October) for sprouting or grinding, or pick flower heads through the May-September flowering season and dry them for tea.

Storage

PFAF: dry seed can be ground into flour and stored like other cereal/legume flours; dry flower heads for tea, stored airtight out of light.

Crimson Clover, a Fast-Growing Green Manure with Edible Seed

Dense, conical flower heads

RHS: dense, conical heads of red flowers appear in summer, a good nectar source for bees.

Grown as a nitrogen-fixing green manure

RHS: sometimes grown as a nitrogen-fixing cover crop and green manure -- PFAF adds it is fast-growing and effectively weed-suppressing too.

Tolerant of a range of soils

PFAF: succeeds in light, medium or heavy soils, even nutritionally poor ground, provided it gets full sun and reasonably moist conditions.

A genuinely hardy annual

PFAF: hardy to UK zone 4 and "not frost tender" -- RHS separately rates it H4 (-10 to -5C).

Flowering from May to September

PFAF: in flower from May to September, with seed ripening from July through October.

Used in soil reclamation

PFAF: beyond the garden, crimson clover is used in soil reclamation projects for its fast, weed-suppressing, nitrogen-fixing growth.

Seeds can be sprouted or milled

PFAF: seeds can be sprouted and eaten in salads, or dried and ground into a nutritious flour.

Three-leaflet foliage

RHS: leaves are composed of three leaflets, on a slender, upright annual or short-lived perennial to about 45cm tall.

Dried flowers make a tea substitute

PFAF: dried flower heads are used as a tea substitute, alongside the plant's more familiar role as a cover crop.

References

1. Plants For A Future (PFAF) - Trifolium incarnatum

   Habitat: grassy places, e.g. near the Lizard peninsula in Cornwall; western/southern Europe to the Balkans and Mediterranean. Hardiness: UK zone 4, not frost tender, USDA 3-9. Soil: light/sandy, medium/loamy or heavy/clay, well-drained, can grow in nutritionally poor soil, mildly acid/neutral/basic. Sun: full sun, cannot grow in shade. Moisture: prefers moist soil; tolerates strong winds but not maritime exposure. Size: annual to 0.5m, medium growth rate, in flower May-September. Propagation: pre-soak seed 12 hours in warm water, sow spring to early summer in situ; can also be sown in early autumn as a winter green manure. Edible use: seeds sprouted and eaten in salads, or dried and ground into a nutritious flour; dried flower heads used as a tea substitute. Medicinal use: none known. Other use: fast-growing, weed-suppressing, nitrogen-fixing green manure; used in soil reclamation projects. Safety: no known hazards to people; avoid planting near camellias or gooseberries as it can harbour a mite affecting those plants.

2. Royal Horticultural Society - Trifolium incarnatum (crimson clover)

   Hardiness H4 (-10 to -5C). Soil: chalk, clay, loam, sand. Position: full sun, east/south/west-facing. Exposure: sheltered. Size: height/spread 0.1-0.5m, 1-2 years to maturity. Moisture: moist but well-drained or well-drained. pH: acid, alkaline or neutral. Propagation: by seed. Pests: generally pest-free. Diseases: generally disease-free. Description: slender, upright annual or short-lived perennial to 45cm, leaves of three leaflets, dense conical heads of red flowers in summer, good nectar source for bees; sometimes grown as a nitrogen-fixing cover crop and green manure.

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.