Sinapis alba
white mustard
Overview
Sinapis alba is an erect annual reaching 12-30 inches (30-75 cm), with bristly-hairy, branching stems. The lower leaves are pinnately lobed (lyre-shaped) and coarsely toothed, up to 6 inches (15 cm) long, while the upper leaves are smaller and less divided. Yellow four-petalled flowers, about 0.4-0.6 inch (10-15 mm) across, are carried in elongating clusters from June to August. The seed pods are bristly, 1-1.6 inches (2.5-4 cm) long, and end in a long flattened beak that often holds the topmost seed; each pod contains several pale yellow to straw-coloured seeds. It is grown for its seed, used in table mustard and as a spice, and as a fast cover and green-manure crop. Frost ends growth, confining it to the frost-free season, and like other brassicas it can host clubroot where these crops are grown in close rotation.
Native Range
Native to the Mediterranean region and southwestern Asia, where it grows on open and disturbed ground. It has long been cultivated for its seed and is now grown and naturalised across temperate regions worldwide.Suggested Uses
Grown for mustard seed and as a leafy salad or microgreen, and widely sown as a fast cover crop and green manure that smothers weeds and adds organic matter. The summer flowers are worked by bees and hoverflies. It also features in short rotations on bare ground between main crops.How to Identify
Appearance
Size & Dimensions
Height1' - 2'6"
Width/Spread8" - 1'4"
Bloom Information
Yellow flowers open from June to August, a few weeks after sowing, and continue over several weeks. Flowering and pod set overlap, with lower pods filling while the cluster keeps lengthening and opening new flowers.
Detailed Descriptions
Foliage Description
GreenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Water & Climate
Water Needs
Care & Maintenance
Care Guide
Sinapis alba grows in full sun on most fertile, free-draining soils at a soil pH of about 6.0-7.5. It germinates and grows quickly in cool, moist conditions and can be sown from spring through late summer. Steady moisture supports leafy growth, while drought cuts it short and hastens flowering. Little added nitrogen is needed on average soils, and as a cover crop it is often sown after a main crop is lifted. Frost kills the plant, ending the season. It is kept out of tight rotations with related brassicas to limit clubroot and other shared problems.Pruning
As an annual, Sinapis alba is not pruned. Grown as a green manure it is cut or dug into the soil at flowering, before seed sets, to add organic matter and limit self-seeding.✓ Toxicity
Non-toxicPlanting Guide
Planting Methods & Timing
Planting Method
direct sow
Direct Sow Timing
Spring through late summer, on bare ground after the last frost
Days to Maturity
60–90 days
Plant Spacing
4 inches