Fast to bolt in heat. Succession sow every 3 weeks through cool weather. Let some plants go to seed — you'll always have a supply, and the seeds (coriander) are a spice in their own right.
Plant window opens
May 01
Last chance to plant
Aug 20
Last frost
~May 15
Days to harvest
45–70 days
Difficulty
Easy
Plant now — Zone 3
Harvest: Jun – Jul, Sep – Oct
Planting Calendar
In Zone 3, Cilantro / Coriander can be planted outdoors from May 01 — the window closes around Aug 20.
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Direct sow. Cool weather is key — bolts quickly in heat. Sow a fresh batch every 3 weeks.
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What Zone 3 growers say about Cilantro / Coriander
plant team · Zone 3
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Care Guide
Sunlight
Full sun to partial shade · 4–8 hrs/day
Watering
Moderate
Spacing
6–8 inches
Soil
Well-draining, light loam
Days to maturity
45–70 days
Soil pH
6.2–6.8
Plant tip · Zone 3
Direct sow. Cool weather is key — bolts quickly in heat. Sow a fresh batch every 3 weeks.
How to know it's ready
Pick leaves before flowering. Once it bolts, leaves become lacy and bitter.
Watering Cilantro / Coriander
How often
Every 2–3 days
How much
1 inch per week
Method
Either method
Overwatering signs
Yellowing, root rot
Underwatering signs
Wilting, rapid bolting
Feeding Schedule
How often
once at planting
Feed type
Balanced fertilizer (light)
Key timing
at planting
NPK: 10-10-10 at half strength
Fast-growing and light feeder. One application at sowing is enough. Over-feeding speeds bolting.
Example product: Half-strength fish emulsion
Reminder: every 21 days after feeding
Succession Planting
Sow every 2 weeks
Sow every 2 weeks from spring through autumn. Cilantro is the most determined bolter in the herb garden — it can go from seedling to flower in 3–4 weeks in warm weather. There is no saving a bolted cilantro plant for leaf harvest. The only reliable approach is frequent new sowings. In summer, choose slow-bolt varieties and still expect faster cycling than in spring. Let a few plants go to seed — coriander seed is a useful spice and the plants will self-sow.
Direct
Direct sow — cilantro bolts quickly and dislikes transplanting. Sow every 2–3 weeks for continuous harvest.
Container friendly · Minimum 1 gallons
Good container herb. Deep pots preferred (taproot). At least 8 inches deep.
Bolting risk: high
Triggers: Heat, long days, drought stress
Prevention: Choose slow-bolt varieties (Leisure, Calypso). Plant in cool season. Keep well watered. Succession sow every 2 weeks. Provide shade.
Once bolting starts, harvest all leaves immediately and let it go to coriander seed — equally useful.
Companion Planting for Cilantro / Coriander
What you plant near cilantro / coriander makes a real difference — here's what to plant, when, and why.
Pest deterrent
Tomatoes
Coriander flowers attract predatory wasps
Plant at same time
Structural
Spinach
Compatible cool-season crops
Plant at same time
Keep away from
Fennel— Inhibits germination
Pests & Diseases
Know what to look for before it gets out of hand — early identification is the most important step.
Aphids
pestmedium
What to look for
Clusters of tiny soft insects on new growth and leaf undersides. Leaves curl, yellow, or become sticky with honeydew. Sooty black mold may follow.
Cause
Multiple aphid species. Populations explode rapidly in warm weather.
Organic treatment
Blast off with strong water jet. Apply insecticidal soap or neem oil directly to colonies. Introduce ladybugs or lacewings.
Prevention
Plant marigolds and nasturtiums nearby. Avoid excess nitrogen fertilizer which creates soft, aphid-attractive growth. Encourage beneficial insects.
Carrot fly
pestlow
What to look for
Root damage and wilting. Cilantro and dill are in carrot family and attract same pests.
Cause
Psila rosae. Affects all members of the carrot family.
Organic treatment
Grow under fine insect mesh.
Prevention
Insect mesh. Grow away from carrots and parsnips.
Leaf spot
diseaselow
What to look for
Dark brown spots on leaves. Affected leaves yellow and die.
Cause
Bacterial or fungal leaf spot. Favoured by wet conditions.
Organic treatment
Remove affected leaves. Copper-based fungicide.
Prevention
Water at soil level. Good spacing.
Recommended Varieties
Leisure (slow bolt — the key feature)
Calypso (very slow bolt, high yield)
Confetti (lacy leaves, slow bolt)
Santo (classic, reliable)
Leisure and Calypso are dramatically slower to bolt than standard varieties — the difference is significant in warm gardens.
Cilantro is in the carrot family — avoid following other Apiaceae crops.
Storing Your Harvest
Room temp
3–5 days in a glass of water like flowers
Fridge
1 week in a glass of water in the fridge, covered with a bag
Freezer
Blend with water, freeze in ice cube trays — excellent for curries
Cilantro is one of the most perishable herbs. The water-glass method in the fridge is the most effective.
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Common questions
In Zone 3, direct sow cilantro / coriander outdoors May 1 – Jun 1, Aug 1 – Aug 20 after your last frost of approximately May 15. Direct sow. Cool weather is key — bolts quickly in heat. Sow a fresh batch every 3 weeks.
Zone 3 has an average last spring frost around May 15 and a first fall frost around Sep 15. These vary by location — the plant app uses your ZIP code with NOAA data for precision.
Good companions for cilantro / coriander include Spinach, Tomatoes. Avoid planting near Fennel.
Cilantro / Coriander typically takes 45–70 days to harvest in Zone 3. Expected harvest window: Jun – Jul, Sep – Oct.
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