Cilantro is the herb people either love or cannot stand — and the one that bolts faster than any other herb in the garden. That bolting habit shapes everything about starting it: cilantro is normally direct-sown, because it dislikes transplanting and because it grows fast enough (45–60 days) that indoor starting buys you almost nothing.

Grown well, cilantro germinates in 7–14 days, matures in 45–60 days, and wants part shade — morning sun with afternoon shade, which also delays bolting in warm weather. Water needs are moderate, cold tolerance is hardy, and it grow best in soil with a pH of 6.0–7.0 at 6–8-inch spacing. Good companions include tomatoes, peppers, marigolds, cabbage. The pests to watch for are carrot rust fly, aphids, wireworms. It is normally direct-sown outdoors — indoor starting is a limited workaround, not the standard method.

Cilantro at a glance

Growing factor What this crop needs
Days to germination 7–14
Sowing method direct sow
Days to maturity 45–60
Soil pH 6.0–7.0
Spacing 6–8 inches
Sun part shade
Cold tolerance hardy

When to start Cilantro seeds indoors

Cilantro is normally direct-sown rather than started indoors, so the timing below is for outdoor sowing — with the indoor option covered honestly at the end. Cilantro is normally direct-sown outdoors, not started indoors. Sow in cool weather: 2–3 weeks before your last frost in Zones 3–5, through autumn and winter in Zones 8–9, and in the cooler months in frost-free Zones 10–13. It bolts within weeks once temperatures climb, so succession-sow every 2–3 weeks for a continuous supply. If you do start indoors, use soil blocks or peat pots and transplant very young — and expect some plants to bolt from the disturbance. Your local extension service can confirm the best sowing windows locally. Use the frost-date calculator to pin down your last frost. Zones 11–13 are frost-free, so timing there follows heat and the cool season instead.

What you need

You do not need much: fine, sterile seed-starting mix (not garden soil), cell trays or small pots, a tray to catch water, a spray bottle or fine watering can, labels and a marker, and a clear lid or cling film to hold humidity until germination. A grow light is the one item that transforms results — a sunny windowsill can work, but lights give stocky seedlings instead of leggy ones. The grow-light calculator helps size a light for your setup, and the seed-spacing calculator shows how many plants fit your beds at 6–8-inch spacing. Check old packets with the seed-viability checker.

Step by step: starting Cilantro seeds indoors

First, the honest version: Cilantro is usually direct-sown, because it does best when its roots are never disturbed. These are the direct-sowing steps most gardeners should follow — with the limited indoor option at the end.

  1. Prepare the bed. Work the soil until fine, loose and free of stones, and rake it level. Cilantro wants soil with a pH of 6.0–7.0.
  2. Sow at the right depth. Sow seed ¼–½ inch deep, direct-sown, spaced for the final plant size. Too deep and seed may never emerge; left on the surface it dries out.
  3. Water gently. Mist or use a fine rose so seed is not washed away. Keep the seedbed damp for the whole 7–14-day germination window — a board or burlap over the row helps.
  4. Wait, and keep it damp. Germination takes 7–14 days. Check daily; one dry day can kill a row of sprouting seed.
  5. Thin ruthlessly. Once seedlings are an inch or two tall, thin to 6–8 inches apart. Thinning feels wasteful, but it is what makes the remaining plants grow.
  6. Mulch and water. Once established, mulch around (not against) the stems and water at soil level. Our watering calculator can help with amounts.

The indoor option, if you need it: sow into soil blocks or biodegradable peat pots of fine seed compost, ¼–½ inch deep, direct-sown, and keep warm and moist until germination in 7–14 days. Transplant the whole block or pot while seedlings are tiny — within 2–3 weeks — and never pull a seedling out bare-root. Even done carefully, expect some check to growth; direct sowing is the reliable route.

Light for seedlings

Light separates stocky seedlings from leggy ones. Give Cilantro seedlings 14–16 hours of light a day, with the source just 2–4 inches above the plants — raise it as they grow. A south-facing windowsill can work in spring, but turn trays daily or seedlings lean towards the glass, and on cloudy weeks even a good window is not enough. Our sunlight calculator tells you how much direct sun a spot gets, and the grow-light calculator helps size a light. If seedlings stretch, the light is not close or bright enough.

Watering seedlings

Seedlings want steady moisture, not wet feet. Water from below where possible — stand the tray in a shallow dish for ten minutes and let the compost wick it up — because overhead watering knocks tiny seedlings flat and keeps stems wet, which invites damping off. Check trays daily, since seed compost dries fast under lights, and Cilantro has moderate water needs — keep the compost evenly moist but never soggy. Mist the surface lightly after sowing until germination, then switch to bottom watering. As transplanting approaches, let compost dry slightly more between waterings to toughen seedlings up.

Hardening off

Hardening off is the week that decides whether seedlings thrive or sulk. Over 7–10 days before transplanting, put trays outside for a few hours a day in a sheltered spot, increasing time, sun and wind exposure each day, and bring them back in at night. Start with shade and still air; end with a full day outside if temperatures allow. Seedlings that go straight from a warm room to open ground get sunscald, windburn or a cold check that sets them back for weeks. Cilantro is hardy — it tolerates light frost, so it can go outside earlier than tender crops. Do not rush this step, and bring trays in if frost threatens.

Transplanting outdoors

Transplant on a cloudy day or in the evening, when the sun will not immediately stress seedlings. Water the trays an hour before, dig holes at the final spacing of 6–8 inches, and set each seedling at the same depth it was growing. Firm soil gently around the roots, water each plant in well, and mulch around (not against) the stems. Good companions for Cilantro include tomatoes, peppers, marigolds, cabbage. Watch for carrot rust fly, aphids, wireworms in the first weeks — the pest-identifier helper can help name anything you find. Water daily for the first week while roots establish.

Common problems and fixes

Problem Likely cause Fix
Bolting within weeks Heat or transplant shock Sow in cool weather; direct sow; succession-sow.
Patchy germination Dry seedbed Keep soil moist for the 7–14-day germination window.
Seedlings wilting after transplant Root disturbance Transplant soil blocks whole, while very young.
Damping off indoors Wet compost Bottom-water and ventilate; prefer direct sowing.

Bolting within weeks

Heat or transplant shock is the usual culprit. Sow in cool weather; direct sow; succession-sow. If badly affected, re-sow — a fresh sowing usually overtakes a struggling seedling within two weeks.

Patchy germination

Dry seedbed is the usual culprit. Keep soil moist for the 7–14-day germination window. If badly affected, re-sow — a fresh sowing usually overtakes a struggling seedling within two weeks.

Seedlings wilting after transplant

Root disturbance is the usual culprit. Transplant soil blocks whole, while very young. If badly affected, re-sow — a fresh sowing usually overtakes a struggling seedling within two weeks.

Frequently asked questions

Can you start cilantro indoors?

You can, in soil blocks, but direct sowing works better — cilantro dislikes root disturbance and grows fast enough that indoor starting gains little.

Why does my cilantro keep bolting?

Heat. Cilantro bolts in warm weather; grow it in spring and autumn, and sow little and often.

How long does cilantro take to grow?

About 45–60 days to harvest, and you can snip leaves much sooner.

Is cilantro the same as coriander?

Yes — cilantro is the leaf, coriander is the seed of the same plant. Let a few plants bolt and you get both.

Does cilantro need full sun?

It tolerates part shade, and in warm climates afternoon shade actually delays bolting — useful in Zones 8 and above.

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