White mustard
Also known as
Yellow mustard, Common white mustard, White charlock, Sinapi
Keep this plant’s care guide close at hand.
Get the appAbout White mustard
Sinapis alba, commonly called white mustard, is a fast-growing, cool-season annual in the cabbage family (Brassicaceae) native to the Mediterranean Basin and widely naturalized across temperate regions worldwide. Plants typically reach 30–120 cm, forming erect, branching stems with coarse, lobed basal leaves and smaller upper leaves. Clusters of bright yellow, four-petaled flowers mature into bristly pods (siliques) that hold the pale yellow seeds used to make mild table mustard. In addition to culinary seed and edible young greens, white mustard is valued as a cover crop and green manure: rapid biomass production protects and enriches soil, while glucosinolates contribute to biofumigation, suppressing some soilborne pests and pathogens. It prefers full sun, moderately fertile, well-drained loam, and neutral to slightly alkaline soils. The crop is quick to mature—baby greens in 30–45 days, seed in roughly 80–100 days—making it suitable for succession sowing. Heat accelerates bolting and can reduce quality, and common pests include flea beetles, aphids, and caterpillars; rotation, row covers, and steady moisture support healthy growth.
Taxonomy
Properties & Requirements
How to care for White mustard
Water
Keep soil evenly moist from sowing through early growth; shallow roots need consistent moisture to avoid stress and flea beetle damage. Provide about 2.5 cm (1 inch) of water per week from rain and irrigation, adjusting for heat, wind, and soil texture. Water seedlings lightly and frequently until established, then deep-water less often to encourage rooting. Avoid waterlogging and prolonged drought. Drip lines or soaker hoses minimize leaf wetness and disease; mulch lightly to steady moisture and reduce splashing.
Light
Provide full sun for best biomass and seed set—at least 6–8 hours of direct light daily. Plants tolerate light, dappled shade (4–6 hours), though growth slows and disease pressure may increase with reduced airflow. In very hot climates, brief afternoon shade can limit heat stress and premature bolting. If trialing indoors or in protected structures, use high-intensity supplemental lighting and ample ventilation; insufficient light produces lanky growth and fewer flowers.
Nutrients
White mustard is a modest feeder. Before sowing, mix in finished compost or a balanced, slow-release fertilizer (e.g., 5-5-5) at recommended rates. On lean soils, a light nitrogen side-dress 3–4 weeks after emergence supports rapid vegetative growth; avoid excess nitrogen, which encourages soft growth and lodging. Sulfur additions can enhance glucosinolate content for biofumigation, but are unnecessary for casual edible use. If grown as a cover crop, fertilizer is usually unnecessary—plant into residual fertility and incorporate biomass at flowering.
Temperature
A cool-season annual, white mustard germinates from about 5–30°C, with best growth between 10–20°C. It tolerates light frosts once established but can be damaged by hard freezes; protect young stands if temperatures dip below –2°C. Sustained heat above 28–30°C drives rapid bolting and lowers leaf quality. In containers or small plots, provide good air flow to limit disease during cool, humid spells. Time plantings to spring and fall in warm climates, or late spring through summer in cool regions.
