Fresh coriander is one of those herbs that can disappear from the fridge just when you need it. Growing your own gives you a convenient supply for curries, salads, salsas and noodle dishes, but there is a catch: coriander does not behave like rosemary or mint. It grows quickly, flowers readily and eventually finishes its life. The trick is to grow several small batches rather than expecting one pot to keep producing for months.
You can grow coriander on a bright windowsill, in a patio container or directly in a garden bed. For the longest supply of leaves, give it good light without excessive summer heat, keep the roots comfortably moist and sow again before the first batch is exhausted.
Decide whether you want leaves or seeds
Coriander, Coriandrum sativum, is an annual plant. Its leafy growth is often called cilantro in American recipes; its dried seeds are usually sold as coriander seed. Both come from the same plant, but the best growing approach differs depending on what you want to harvest.
For fresh leaves, aim for compact, leafy plants and regular sowings. Hot, dry conditions encourage them to send up flowering stems, a process gardeners call bolting. Once flowering starts, the plant directs more of its energy towards seeds and becomes less useful as a source of tender leaves.
For seeds, allow selected plants to flower and ripen. Give them more room and a sunny position so they can complete their life cycle. You can also eat the flowers and use immature green seeds in cooking, so a flowering plant is not a total loss.
Choose a place that suits the season
Outdoors, coriander likes free-draining soil and a sunny or lightly shaded position. In spring, a sunny bed or container works well. During a hot summer, some shade around midday can help leaf crops stay productive for longer. A sheltered patio is useful, but a dark corner will give weak, stretched growth.
Indoors, use the brightest suitable windowsill you have, while watching for fierce heat behind glass. Coriander grown in a warm kitchen with poor light often turns pale, becomes leggy and flowers early. If a windowsill is very hot in the afternoon, move the pot slightly away from the glass or use a brighter, cooler spot.
Don't confuse an indoor pot with an endless herb supply. It is a convenient short-term crop, especially in winter when outdoor growing is limited, but fresh sowings are still necessary. In the UK, outdoor plants generally give the most dependable leafy harvests from spring into autumn.
Pick the right pot and compost
Choose a container with drainage holes so excess water can escape. A reasonably broad pot or trough is more useful than a tiny decorative herb pot because it holds more compost and lets you grow a small group of plants without crowding them severely. Put a saucer underneath indoor pots, but empty standing water rather than leaving the roots soaked.
Use peat-free multi-purpose compost for established container crops, or peat-free seed compost for starting seedlings. Firm it gently so seeds make contact with the surface, without packing it down into a hard block. In a garden bed, remove weeds, loosen compacted soil where needed and rake the surface into a fine texture.
You may have seen supermarket coriander sold as a thick tuft of slender stems. Those pots are usually packed with seedlings intended for quick cutting, not long-term cultivation. If you already have one, you can try separating small groups and repotting promptly, but starting from seed is usually simpler. The RHS advises keeping supermarket-bought coriander in indoor containers to reduce plant-health risks.
Sow coriander seeds without overcrowding
For an indoor windowsill crop, you can start sowing from February in a warm, bright position. Outdoors, sow from spring into autumn when conditions are suitable. Avoid putting tender seedlings straight into cold, saturated soil simply because a calendar says it is spring.
Fill the pot or prepare the soil, then scatter or place seeds about 5cm apart. Cover with a thin layer of compost or soil and water gently with a fine rose so you do not wash the seeds into one corner. Label the pot with the sowing date. You do not need to bury the seeds deeply.
Indoor seeds commonly take around two to three weeks to germinate; outdoors the RHS gives a range of roughly one to three weeks depending on temperature. Keep the compost just moist while waiting. If nothing appears immediately, resist digging through the pot to check every seed.
Thin crowded indoor seedlings to roughly 5cm apart once they are sturdy enough to handle. For outdoor plants intended mainly for leaves, you can harvest selectively from relatively close plantings. If you are growing mature plants for seed, thin to about 20cm apart so they have space to flower and ripen.
Keep the plants watered, not waterlogged
Coriander's roots need both moisture and air. A pot that dries out repeatedly can trigger early flowering, while one that remains saturated can cause poor growth and root problems. Check the compost with a finger rather than watering automatically at the same hour every day.
Containers can dry quickly in warm or windy weather. Water when needed to keep the compost lightly and evenly moist, allowing surplus water to drain away. Garden-grown coriander generally needs less attention, although a prolonged dry spell is a good reason to water thoroughly.
Water near the base of the plants to avoid flattening young seedlings. Morning watering is convenient in summer, as it gives plants a supply before the hottest part of the day. A little observation is more valuable than a rigid schedule: a small pot on a sunny windowsill may need water much more often than a garden row after rain.
Sow a new batch before the old one flowers
This is the step that makes home-grown coriander worthwhile. Sow a modest number of seeds every few weeks through the growing season instead of planting everything on one day. The RHS suggests small, regular batches for a continuing leaf crop; the exact interval can be adjusted to how quickly you use it.
If you cook with coriander twice a week, keep one pot producing, another developing and a third newly sown when space allows. By the time the oldest plants begin flowering, the next batch should be approaching picking size. You do not need a greenhouse or an elaborate growing system.
Summer sowings for leaves benefit from a cooler position away from harsh midday sun. Autumn sowings may continue under a cloche or in a greenhouse, depending on conditions. Indoors, new pots can extend your supply, although winter light is often the limiting factor.
Harvest leaves without stripping every stem
Start taking leaves when plants are around 10–15cm tall. Snip or pick a few suitable leaves from each plant and leave enough healthy foliage for it to recover. Taking every leaf from a young seedling may end its usefulness rather than encouraging more growth.
A group of plants can give several small pickings, with time between harvests for fresh leaves to develop. Use the leaves promptly for the best flavour. If you have cut more than you need, refrigerate them for a short period in a suitable covered container rather than leaving them exposed to dry out.
You can also grow coriander as microgreens, harvesting whole young seedlings after a couple of weeks. That is a different approach: it gives a quick, single harvest rather than repeated leaf pickings from mature plants. Choose whichever suits your cooking habits.
What to do when coriander starts flowering
Look for a central stem stretching upwards, finer-looking upper leaves and developing flower buds. You can remove flower stems early to prolong leafy growth, but you cannot keep an annual plant in its leafy stage indefinitely. In persistent heat, sowing again is usually more productive than repeatedly cutting back an exhausted plant.
If you want coriander seed, leave a few healthy plants to flower. The delicate blooms are edible, and the developing green seeds have a milder flavour than dried ones. For fully ripe seed, wait until it has browned, then cut stems carefully into a paper bag so the seeds do not scatter.
Spread harvested seed in a warm, airy room until thoroughly dry before putting it into a sealed jar for cooking or a labelled paper envelope for sowing. Store it somewhere cool and dry. Do not seal damp seed in an airtight container, where mould may develop.
Solve the common problems
Tall, weak seedlings: Light is probably insufficient, or plants have been left crowded. Move them somewhere brighter and thin gently. Avoid trying to compensate with heavy feeding.
Plants flowering almost immediately: Hot weather, dry compost or the natural age of the plant may be responsible. Move future summer sowings out of the midday sun, water consistently and use successive sowings.
Yellowing or collapsing seedlings: Check whether compost is continually wet and whether air can circulate. Waterlogging and fungal problems are more likely in crowded, poorly drained pots.
Holes in outdoor leaves: Slugs and snails may be feeding on young plants. Check around pots and beds, especially after damp nights, and protect vulnerable seedlings using suitable garden methods.
No germination: Check the seed's age, whether the surface dried out and whether the sowing conditions were too cold. Start a fresh small pot rather than endlessly soaking a failed batch.
A simple home-growing routine
Begin with one well-drained pot of seeds in a bright position. Keep it moist, thin the seedlings and start another pot a few weeks later. Once leaves are large enough, harvest sparingly and regularly. If a plant bolts, use what is still good, consider saving its seed and let the next sowing take over.
That approach works whether you have a vegetable plot or only a kitchen windowsill. Coriander is not difficult to grow; it simply rewards gardeners who understand that a steady supply comes from successive plants, not one everlasting pot.
Sources and further guidance
The Royal Horticultural Society's coriander growing guide covers sowing, indoor and outdoor conditions, harvests, bolting and seed collection. Its general guide to growing and harvesting herbs explains how coriander fits alongside other culinary herbs.