Common sowthistle
Also known as
Sow thistle, Smooth sowthistle, Annual sowthistle, Hare's lettuce, Puha (pūhā)
Keep this plant’s care guide close at hand.
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Sonchus oleraceus, commonly called common sowthistle, is a fast-growing annual (occasionally biennial) in the Asteraceae. Erect, hollow, branching stems 30–150 cm tall exude a milky latex when cut. Basal leaves are deeply lobed with soft, pliable spines; upper leaves are glabrous, bluish-green, and have rounded auricles that clasp the stem. Flat-topped clusters of dandelion-like yellow flower heads (1.5–3 cm) appear from spring to autumn, maturing to ribbed achenes topped with a white pappus for wind dispersal. A pioneer of disturbed ground, it thrives in fertile, moist, well-drained soils and tolerates compaction, variable moisture, and a wide pH range. Young leaves are edible as a slightly bitter pot herb, especially in cool weather before flowering. In cultivation it is short-lived and reseeds freely; in many regions it is both a cosmopolitan agricultural weed and a valued leafy forage or traditional vegetable.
Taxonomy
Properties & Requirements
How to care for Common sowthistle
Water
Keep soil evenly moist but not waterlogged. In garden beds, provide roughly 2.5 cm of water per week from rain or irrigation, increasing slightly in sandy soils or windy sites. In containers, water when the top 1–2 cm of mix dries; saturate thoroughly, then drain. Consistent moisture yields tender leaves and reduces bitterness. Ensure sharp drainage—avoid standing water, which encourages root issues and weak, sappy growth.
Light
Full sun to part shade. In cool seasons or mild climates, 6+ hours of direct sun produces the most biomass. In hot regions or midsummer, provide light afternoon shade or dappled light to keep leaves tender and delay bolting. Indoors, place at a bright south- or west-facing window, or supplement with strong grow lights for 12–14 hours daily. Low light leads to lanky, floppy growth and fewer usable leaves.
Nutrients
This species grows well with modest fertility. Mix mature compost or a light application of balanced organic fertilizer into the soil before sowing. For containers, feed with a dilute balanced liquid (e.g., 10‑10‑10 at 1/4–1/2 strength) every 3–4 weeks during active growth. Avoid heavy nitrogen, which can cause soft, floppy growth and elevate nitrate accumulation in leaves. Maintain even moisture to keep nutrients available.
Temperature
A cool-season grower that thrives between 10–24°C (50–75°F). Seeds germinate from about 5–25°C (41–77°F). Plants tolerate brief, light frosts (around −3°C/27°F) once established but are damaged by hard freezes. In hot weather above ~27–30°C (80–86°F), growth slows, plants bolt, and leaves become more bitter; provide afternoon shade and steady moisture in warm climates. Not suitable for sustained high heat without shade and irrigation.
