Seeds 30 Seeds (Mentha arvensis)

Field mint (Mentha arvensis), also known as corn mint, is a hardy perennial prized for its high natural menthol content, giving the leaves an unusually crisp, cooling aroma and a clean, refreshing bite. The plant carries small, softly toothed oval leaves on square stems and spreads vigorously into a dense aromatic carpet, making it as useful as ground-bordering greenery as it is in the kitchen. Its bright menthol flavour shines in hot and iced teas, lemonades and cold drinks, yoghurt and tahini sauces, salads and as a fresh garnish, while the strongest oils develop in young shoot tips harvested just before flowering.

Planting

Start field mint seed indoors in spring, about 6 to 8 weeks before your planting-out date, and move seedlings outside once any danger of frost has passed. Surface-sow the seed: press it gently onto the surface of moist growing medium and leave it uncovered, because mint needs light to germinate. Keep the medium consistently moist and well-lit, and expect germination in about 10 to 14 days at 22 to 24 C (the RHS reports roughly two weeks at around 20 C). Once seedlings have several leaves, pot them up into a 7.5 cm pot, then set plants out about 45 cm apart, in rows about 45 cm apart. Choose a spot in full sun to partial shade with at least 4 to 6 hours of sun per day; mint is most productive in full sun but tolerates light shade. Note that field mint is more commonly and reliably propagated vegetatively, by dividing an established clump or rooting stem and runner cuttings.

Fertilizing

Field mint prefers a rich soil high in organic matter, so before planting work plenty of compost or well-rotted manure into the bed to feed the plants and improve drainage; aim for a soil pH of 6.0 to 6.5. In well-amended soil the plant may need no extra fertilizer at all. Where you do feed, apply nitrogen from spring to early summer to match the plant's active growth. Avoid overdoing the nitrogen: excess produces soft, weak growth that attracts spider mites and aphids and can make disease worse.

Care

Keep the root zone consistently moist but never waterlogged, and never let the plants wilt between waterings. Water the soil directly rather than the leaves to cut down on leaf disease, and water deeply instead of giving frequent light sprinklings; drip irrigation is preferred over overhead watering. Cut shoot tips and individual leaves regularly once plants are established, as frequent cutting keeps the plant bushier; young, soft tips carry the most intense flavour, and removing flower spikes keeps the leaves tasting their best. For drying or the strongest oil, cut the whole plant just as the flower buds begin to appear. After flowering, cut the plant back to about 5 cm from the base to push out fresh new growth, and divide established clumps every 3 to 4 years to keep them vigorous. Watch for mint rust, aphids, spider mites (which thrive in hot, dry conditions and with excess nitrogen) and verticillium wilt; dislodge aphids and mites with a strong jet of water or insecticidal soap, and always start from disease-free stock to guard against wilt.