How to Grow White Mustards USA | Complete Growing Guide

At a Glance

Quick Facts

Factor	Value
Sunlight	6-8 hours direct sun
Minimum survivable temp	-10C
Drainage	Fertile, well-drained (RHS); NDSU: avoid drought-prone sandy soils, prefers good moisture.
Lifecycle	Annual herbaceous plant. RHS rates it H4, hardy through most of the UK (-10 to -5C).
Edible parts	seeds, leaves

Growth Stages

Stage	BBCH	Notes
Sowing	0	NDSU: sow late April to mid-May, 0.5-1.5in deep into a moist, firm seedbed via drill or air seeder -- early planting on a firm seedbed supports vigour. RHS: propagate by seed into fertile, well-drained soil in full sun.
Seedling establishment	1	NDSU: flea beetles cause early-season "shot-holed" damage on seedlings -- treatment is only warranted once defoliation exceeds 25%. Cool temperatures and good moisture at this stage extend flowering and boost eventual yield.
Flowering	6	RHS: bright yellow flowers appear from May through to August or September, valued as a food source for wildlife.
Pod maturity and harvest	8	RHS: flowers are followed by dark red-to-brown seeds. NDSU: harvest by straight combining once pods are mature and dry, ideally at 12-15% seed moisture, around 85-90 days from sowing.

Harvest & Storage

When to pick: NDSU: harvest by straight combining once pods are mature and dry, ideally at 12-15% seed moisture for best quality -- crop matures 85-90 days from sowing.

Storage

Store dried seed in an airtight container; used to make table and hot-dog mustard, or in processed meats for flavour, emulsification and water binding (NDSU).

Diseases

Clubroot

moderate

Plasmodiophora brassicae

Named by RHS as the main UK disease risk for this brassica-family crop; NDSU's commercial-growing guidance does not mention it, instead flagging Sclerotinia -- a genuine regional difference kept honest rather than…

White mold (Sclerotinia stem rot)

moderate

Sclerotinia sclerotiorum

Named specifically by NDSU as a serious risk in commercial mustard production; recommends avoiding rotation with canola, sunflower or beans to reduce the risk. RHS does not mention it for UK garden growing.

Pests

Cabbage caterpillars

low

Pieris brassicae; Pieris rapae; Pieris napi; Mamestra brassicae; Plutella xylostella

Named by RHS as a general risk for this brassica-family crop.

Flea beetles

moderate

Chrysomelidae: Alticini (various spp.)

Named independently by both RHS and NDSU -- NDSU describes a "shot-holed" leaf appearance on seedlings, treatment warranted only above 25% defoliation.

White-mustard, Seed to Harvest

A pollinator visit

RHS notes white mustard flowers are valued as a food source for wildlife -- bees and other pollinators visit readily through the long May-to-autumn bloom period.

Flowering plants in a bed

RHS describes bright yellow flowers on hairy, erect, branched stems -- the branching habit is easy to see once a patch is in full bloom.

A dense flowering stand

White mustard's compact, branching growth means even a small planting produces a dense mass of bloom.

A field-scale planting

NDSU covers white mustard (as yellow mustard) as a genuine commercial seed crop, grown at field scale for table and hot-dog mustard production.

A close-up flower cluster

Individual flowers cluster densely at the stem tips -- this is the stage that develops into seed pods over the following weeks.

An upright flowering stem

RHS gives a mature height of 0.5-1m -- NDSU's commercial crop reaches a similar 30-45in.

Flowers and forming pods together

As lower flowers finish, pods begin forming behind them while the stem tip continues flowering -- a single plant can show every stage at once.

Grown as a green manure

RHS notes white mustard is grown for fodder, green manure or seed -- a dense planting like this is exactly what a green-manure cover crop looks like in flower.

Seed pods forming

RHS notes flowers are followed by dark red-to-brown seeds -- NDSU recommends harvesting once pods dry down to 12-15% seed moisture.

References

1. North Dakota State University Agriculture Extension - Tame Mustard Production

   Soil: fertile, well-drained, avoid drought-prone sandy soils. Size: 30-45in height, matures 85-90 days. Climate: prefers cool temperatures and good moisture, which extend flowering and boost yield. Planting: seed late April to mid-May, 0.5-1.5in deep in a moist, firm seedbed; ~100,000 seeds/lb, sown at 10-14lb/acre via grain drill or air seeder; early planting and a firm seedbed support vigour. Pests: flea beetles cause early-season "shot-holed" damage on seedlings; treat if defoliation exceeds 25%. Diseases: Sclerotinia (white mould) a serious risk -- avoid rotating with canola, sunflower or beans. Harvest: straight combine when mature and dry, ideally at 12-15% seed moisture for quality. Edible use: table and hot-dog mustard; used in processed meats for flavour, emulsification and water binding.

2. Royal Horticultural Society - Sinapis alba (white mustard)

   Hardiness H4 (-10 to -5C, hardy through most of the UK). Soil: chalk, clay, loam, sand, fertile and well-drained. Sun/aspect: full sun, south/west-facing. Exposure: exposed or sheltered. Size: 0.5-1m height, 0.1-0.5m spread, 1 year to maturity. Propagation: by seed. Pests: flea beetles, caterpillars. Diseases: clubroot. Edible use: grown for fodder, green manure or mustard seed; native British plant, bright yellow flowers May-Aug/Sept, dark red-brown seeds, valued as a wildlife food source.

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.