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How to Grow White Mustards | Complete Growing Guide
Move through the SoilCommander growing library like a course: keep the navigation in place, open the next lesson, and build your garden plan step by step.
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.
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).
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.
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.
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.
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.
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.
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.
Frequently Asked Questions
What problems affect white mustards?
Our data links 2 diseases and 2 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
This page gives you the thresholds; the planner turns them into your own calendar. It works from what you can observe and measure in your garden rather than from dates written for somebody else’s latitude.
Science-based growing guides · Thresholds that hold in any climate
This guide states the conditions the plant itself responds to — soil temperature, frost tolerance, day length — rather than dates, because the same calendar month means opposite seasons in the northern and southern hemispheres. Anything genuinely restricted to one part of the world is named as such rather than presented as universal. Written and maintained by our editorial team against international horticultural research and extension sources.
Sketch your exact plot shape, pick your crops, and get a spacing-accurate bed layout with companion pairings and a rotation plan. Spacing, companion pairings and rotation are the same in every climate and both hemispheres — pair the layout it gives you with when to plant to set your own timing from soil temperature.
