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Cilantro / Coriander

Coriandrum sativum

HerbCool-seasonContainer-friendly Easy

Fast and cool-loving, cilantro gives leaves in weeks then bolts in heat — you can't really stop it, so sow a little every couple of weeks. It's the same plant as coriander (the dried seed).

Growing conditions

Light
Full sun (6+ hours of direct light) in cool spring and fall weather; in summer heat give it light afternoon shade, which slows bolting and extends the leaf harvest.
Water
Medium
Soil
Light, fertile, well-drained loam with some organic matter; tolerates most garden soils but hates waterlogging. Grows well in a deep pot (20–25 cm / 8–10 in) to give the taproot room. · pH 6.2–6.8 (slightly acidic to neutral)
When to sow
It's cool-season and lightly frost-hardy. Make the first sowing around your last spring frost (about the time you'd plant lettuce), as soon as soil is workable, then sow again every 2–3 weeks. For a fall crop, resume sowing in late summer as the heat breaks. Avoid sowing into the peak of summer in hot regions — long days and high heat make it bolt before it makes much leaf.
Spacing
Thin to 8–15 cm (3–6 in) apart for leaf production, or 20–30 cm (8–12 in) apart if you're growing it on for coriander seed; rows about 30 cm (12 in) apart.
Days to maturity
Roughly 45–70 days from sowing for leaf harvest (begin picking when plants are 10–15 cm / 4–6 in tall); about 90–120 days for ripe coriander seed.
Hardiness
Grown as a cool-season annual across USDA zones 2–11; the zone matters less than the season. In cold zones (2–6) sow spring through late summer; in warm zones (8–11) grow it in fall, winter and early spring and skip the hot midsummer, when it bolts almost immediately.

How to grow it

  1. 1

    Direct sow — don't transplant

    Sow seed 0.5–1 cm (0.25–0.5 in) deep right where it will grow, because cilantro's taproot dislikes being moved and sets plants back and triggers early . Keep the seedbed evenly moist and it should in 7–14 days. If you must use containers, sow straight into a deep pot so you never have to disturb the root.

  2. 2

    Thin to give each plant room

    Once seedlings are a few centimetres tall, thin them to 8–15 cm (3–6 in) apart for leaf, or 20–30 cm (8–12 in) for seed. Crowded plants stay spindly, trap humidity and damp off, so don't skip this. Snip thinnings at soil level rather than pulling, so you don't disturb the neighbours' roots — and eat the thinnings.

  3. 3

    Water deeply but let the surface dry

    Give about 2.5 cm (1 in) of water a week, watering at the base and letting the top of the soil dry between waterings. Cool, even moisture grows tender leaves and discourages early ; soggy soil and overhead splashing spread the fungal and bacterial problems cilantro is prone to. Water in the morning so foliage dries by night.

  4. 4

    Feed lightly and mulch

    Cilantro is not a heavy feeder; mix a little into the bed at sowing and, for a long leaf crop, once with a balanced fertilizer. A thin keeps the roots cool and the soil evenly moist, which directly slows in warm weather. Don't overdo nitrogen — lush, soft growth is weaker and no slower to bolt.

  5. 5

    Harvest often and pinch the flowers

    Start cutting outer leaves once plants are 10–15 cm (4–6 in) tall, taking up to a third at a time, which keeps them bushy and productive. As the weather warms the plant will try to (send up a flower stalk); out those flower stems as they appear stalls seed-making and prolongs the leaf harvest a while longer.

  6. 6

    Sow in succession

    Because each plant and is done in a few weeks during warm weather, the only way to keep fresh cilantro coming is sowing: start a small new patch every 2–3 weeks through spring, then resume in late summer for fall. Don't fight the bolt on one planting — replace it. Plants left to flower will self-seed and often pop up on their own next season.

  7. 7

    Let some bolt for coriander seed

    When a planting , lean in: let it flower (the blooms also well and beneficial insects), then watch the green seedheads. Cut whole heads with a length of stalk when about two-thirds of the seeds have turned tan-brown but before they shatter and drop. Hang the stalks upside down in a paper bag in a dry, airy spot for about two weeks to ; the dry seeds fall into the bag.

Gardener's notes

  • 'Cilantro' and 'coriander' are the same plant — in the US, cilantro means the leaf and coriander means the dried seed. Each papery 'seed' you sow is really a fruit holding two seeds, so you often get two seedlings per planting spot.
  • Don't fight the — schedule around it. Trying to keep one planting going all summer is a losing battle; a fresh short sowing every 2–3 weeks, plus afternoon shade and cool, even moisture, is what actually delivers season-long cilantro.
  • Never start it in cell trays to 'get a head start' — the disturbed taproot triggers shock and early , so a direct-sown plant usually outproduces a transplanted one. And cilantro you find no-flavor 'soapy' is genetics on the eater's side, not a growing mistake.

Varieties worth knowing

'Santo'
Slow-bolt standard — vigorous, productive and the most widely grown leaf type; a reliable benchmark other varieties are compared against.
'Calypso'
Slowest-bolting variety available — averages about three weeks longer before bolting than Santo, with lush broad leaves; the top pick for stretching the leaf harvest.
'Leisure'
Slow-bolting Santo-type bred for heat; a good choice for Southern and hot-summer gardens, leaf-ready in about 50–55 days.
'Cruiser'
Upright, uniform and bolt-resistant — its tall, clean habit makes cutting and washing easier; similar schedule to Santo.
'Slow Bolt'
Generic slow-bolting strain, ~50 days to leaf; widely sold and a solid budget option for succession sowing.

Common problems & fixes

Rapid bolting (premature flowering)
Sign: Plant shoots up a tall, ferny flower stalk; leaves turn fine and feathery, growth slows and the flavor goes bitter. Often within weeks in summer.
Fix: This is normal biology, not a disease: heat and long summer days trigger it, and transplant shock or drought speed it up. You can't truly stop it — slow it by direct sowing, choosing slow-bolt varieties (Calypso, Santo, Leisure), giving afternoon shade and steady moisture, and harvesting often. The real solution is succession sowing so a fresh crop is always coming, plus letting a bolted plant make coriander seed.
Aphids
Sign: Clusters of tiny green, gray or black soft-bodied insects on new growth and the undersides of leaves; sticky honeydew, curled or distorted leaves, sometimes sooty mold.
Fix: Knock them off with a strong jet of water, encourage the ladybugs and lacewings the flowers attract, and treat heavy infestations with insecticidal soap, spraying leaf undersides. Avoid excess nitrogen, which fuels the soft growth aphids love.
Bacterial leaf spot
Sign: Small water-soaked, angular spots between the leaf veins that turn dark brown to nearly black; worst in cool, wet weather and crowded plantings.
Fix: Caused by Pseudomonas syringae pv. coriandricola and spread entirely by free moisture (rain, dew, overhead watering). Use clean/treated seed, water at the base in the morning, space and thin for airflow, avoid working among wet plants, and remove and discard infected leaves; rotate where you plant cilantro.
Damping off
Sign: Seedlings suddenly wilt, flop over and rot or pinch in at the soil line, often in patches; stands thin out right after emergence.
Fix: Soil fungi (Pythium, Rhizoctonia) thrive in cold, wet, crowded, poorly drained conditions. Sow into warm, well-drained soil, don't overwater (especially on cool, cloudy days), thin promptly for air circulation, and don't sow too deep or too thick.
Powdery / leaf spot diseases in heat and humidity
Sign: Pale or dark blotches, yellowing and dieback of foliage, especially on stressed, bolting plants in muggy weather (e.g. Alternaria-type leaf spot on leaves and seedheads).
Fix: Improve airflow with proper spacing, keep foliage dry by watering at the base, remove affected leaves, rotate crops, and don't crowd plants. Stressed, bolting plants are most vulnerable, so harvest or replace promptly.

Companions

Grows well with
Tomatoes (the cilantro's flowers draw in beneficial insects)Lettuce and spinach (quick cool-season crops that share its conditions)Peas and beansBasil and dillAnything needing pollinators or aphid predators — the flowers are excellent insectary plants
Keep apart from
Fennel (releases compounds that can inhibit nearby plants and cross-pollinates with other Apiaceae for seed-savers)Lavender, rosemary and other dry-loving Mediterranean herbs (want lean, dry conditions opposite to cilantro's cool, moist preference)

Harvest & storage

Harvest
Two harvests from one plant. For cilantro leaf, begin cutting outer leaves and stems once plants reach 10–15 cm (4–6 in), taking up to about a third at a time and cutting often to keep plants bushy; quality drops once a plant bolts. For coriander seed, let the plant flower and form green seedheads, then cut whole heads when roughly two-thirds of the seeds have turned tan-brown — before they shatter and self-sow.
Storage
Fresh cilantro is best used quickly: stand the cut stems in a glass of water in the fridge, loosely covered, or wrap in a damp towel in a bag, for up to about a week; it also freezes well chopped into ice-cube trays with water or oil. To finish coriander seed, hang the cut seedheads upside down in a paper bag in a dry, airy place for about two weeks to cure; once fully dry, separate seed from chaff and keep in an airtight jar in a cool, dark cupboard. Whole dry seed keeps for a year or more — save some to sow, as it stays viable a year or two.

Sources

This guide is curated from authoritative horticulture references — primarily US university Extension services, the USDA, and the RHS.