How to Grow Crimson Clovers USA

Quick Facts

Factor	Value
Drainage	Moist but well-drained or well-drained (both sources); PFAF: tolerates light, medium or heavy soils, even nutritionally poor ground.
Edible parts	leaves, flowers, seeds

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.

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.

What the research guides add

Crimson clover is grown as a cover crop, and SARE’s guide gives the timing rule that matters: sow before the first frost, not after it.

• Seed six to eight weeks before the average date of first frost, at 15 to 18 lb per acre drilled or 22 to 30 lb per acre broadcast. (SARE)
• Planted in late summer it gives good ground cover and weed control as it fixes nitrogen from the air and scavenges nitrogen from the soil; SARE puts its nitrogen contribution at 70 to 150 lb per acre. (SARE)
• It is gaining popularity as a winter-killed annual, like oats, in zones 5 and colder. (SARE)
• Inoculate the seed if crimson clover has not been grown there before. Strongly acidic soil below pH 5.0, or a phosphorus or potassium deficiency, can virtually shut down nitrogen fixation. (SARE)

Crimson clover in the USA: climate data

Dates are the median 32°F freeze dates and freeze-free days from NOAA NCEI U.S. Climate Normals 1991–2020; zones come from the USDA 2023 Plant Hardiness Zone Map (ZIP code of each city centre).

Sources for this section

• Sustainable Agriculture Research and Education (SARE): Crimson Clover, Managing Cover Crops Profitably

Section researched and checked on 25 October 2026 by the SoilCommander Editorial Team. How we check facts: editorial policy.

Sources

The full list of 2 sources behind this guide (Plants For A Future (PFAF), Royal Horticultural Society) is in the references of our UK guide to crimson clover; they describe the plant itself, which is the same wherever it grows.