CORVALLIS, Ore. — If you plant cilantro in late June or early July, it will flower — or bolt — during long, hot summer days. You may lose the leaves, but you’ll gain coriander seeds.
Both temperature and day length influence flowering and seed set, according to Jim Myers, the Baggett-Frazier Endowed Chair of Vegetable Breeding and Genetics at Oregon State University.
In warm weather, cilantro completes its life cycle faster. In mid-summer, it typically bolts into small white flowers and produces seed within four to six weeks. In the cooler, shorter days of spring or fall, plants grow leaves for several weeks or months before flowering.
Plant timing matters
To delay bolting, plant cilantro in a cooler part of the garden, advised Ross Penhallegon, retired horticulturist with the OSU Extension Service. An even better strategy is to plant in early spring and again in late summer as temperatures cool and day length shortens.
Bolting isn’t entirely negative. Flowers develop into seeds that can be collected, dried and ground into coriander. The blossoms also attract beneficial insects, especially in early morning and evening.
Succession planting for steady harvest
To maintain leafy cilantro throughout the season, sow seeds in succession — small batches planted every few weeks. Avoid planting during peak summer heat, when plants are likely to bolt before producing many leaves.
If leafy harvest is the goal, grow cilantro in a cool or semi-shaded location during the warm season. The herb grows best from direct seeding or from starts, though its long taproot makes transplanting difficult.
Planting directions
Sow seeds directly into sunny, fertile beds from early spring through early summer, then again in early autumn. Plant 10–15 seeds per foot of row and cover with ½ inch of soil. Thin plants to 8 inches apart with rows spaced 18–24 inches. Seeds germinate at soil temperatures of 55–68° F, and mature plants tolerate light freezing.
Every part of the plant has a purpose
Common in Latin American, Asian and many global cuisines, cilantro has become a staple in U.S. kitchens. Fresh leaves add distinctive brightness to salsas, stir-fries and garnishes. They are most flavorful when young and tender.
All parts of the plant are edible:
- Leaves — best used fresh for flavor
- Seeds — harvested before they drop and ground as coriander
- Roots — valued in Thai and Vietnamese cooking, best dug in autumn
Previously titled Plant cilantro in summer and get coriander seeds
