Coriander is a versatile herb that can be grown in both garden beds and containers. Here is what to keep in mind when sowing and planting coriander.
Coriander (Coriandrum sativum) is one of the world’s oldest medicinal and culinary herbs. Its peppery, spicy, and slightly bitter leaves have long been staples in Asian and South American kitchens. With aromatic leaves, seeds, and flowers, this multifaceted herb is worth growing at home. Read on to find out everything you need to know about successfully cultivating coriander in your garden.
Growing coriander at home: the right location
Coriander comes from the Mediterranean and thrives in warm and sunny to semi-shady locations. To harvest fresh coriander leaves, a semi-shady location is best, as more leaves form when the plant is out of direct sunlight.
Coriander grows best in nutrient-rich soil that drains well and has good water retention. For plants grown outdoors, sandy loam is ideal, and for potted coriander, use a high-quality, nutrient-rich potting soil, such as our Plantura Organic All Purpose Compost. Remember: the soil’s pH value should be between 6 and 7 as the herb does not tolerate acidic soils.
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Growing coriander in the garden
Coriander is somewhat susceptible to the cold and should only be sown outdoors from April to May, when the soil has already warmed and the threat of frost has passed. You can plant both coriander seeds and young plants at this point.
How to grow coriander in pots
When cultivating coriander in a pot, use a container with a diameter of at least 15 to 20cm and good water drainage. The larger the pot, the less risk there is that the plant will dry out on hot summer days. Add in a drainage layer of sand, gravel, or expanded clay a few centimetres high at the bottom of the pot to prevent waterlogging and root-rot.
How to grow coriander indoors
Coriander can be cultivated indoors year round. However, it is paramount that the plant is placed in a suitable location. A warm windowsill facing the sun is ideal. Here, coriander leaves will sprout even in winter. Coriander rarely produces flowers indoors, and those that do are unlikely to develop seeds, because there are no pollinators. As such, coriander cultivated indoors can be harvested but not propagated.
How to sow coriander
You can either pre-cultivate your coriander indoors, or sow it directly outdoors. The advantage of pre-cultivating coriander is that once the plants are outside, you can harvest their leaves earlier and their seeds will safely mature in autumn. To pre-cultivate coriander, sow the seeds in pots with nutrient-rich potting soil from the beginning of March. You should not need to prick them out.
If you would rather sow the seeds outside directly, do so from the end of March to the end of April. Plant the seeds 1 cm deep and keep 20 to 25 cm between rows. Coriander seeds must be warm to germinate – around 12 to 22°C. As such, it is a good idea to cover them with a black, heat-collecting foil. Be sure to keep the seeds moist and, if the temperature and humidity are right, the first seedlings will appear after about two to three weeks. As soon as the first seedlings begin to sprout, remove the foil.
If you are planning to cultivate your coriander indoors, you can sow coriander seeds year round.
Sowing coriander: summary
- Indoor cultivation is possible year round
- Pre-cultivate seedlings for outdoor planting from the beginning of March
- Sow directly outdoors from April to the beginning of May (optimum temperatures 12-22°C)
- Sowing depth approx. 1 cm, row spacing in the bed 20-25 cm
- Always keep coriander seeds well moist until germination (around 2-3 weeks)
How to plant coriander
Do not plant out pre-cultivated coriander seedlings before mid-May; they will not react well to the cooler temperatures. To plant your seedlings outdoors, keep 5 cm between individual plants and 15 to 20 cm between bunches. Plant the seedlings as deep as they were in their containers. Water vigorously.
Tip: If you have purchased potted coriander, or if your plant’s current pot is too small, it will need a change of soil. May is an ideal time to repot coriander!
How to propagate coriander
Coriander is an annual that propagates via seeds. Ideally, by autumn, the decorative umbel flowers should have produced seeds, which slowly ripen from September to October. Only harvest these seeds once they have turned from green to brown.
Coriander seeds fall off easily in dry conditions. As such, it is best to harvest the seeds in the morning when the umbels are still damp and tough from dew. Cut off entire seed stalks and let them dry out indoors for a few weeks. The coriander seeds will detach themselves from the umbels once they are sufficiently dry. When stored in a cool, dark place, properly harvested coriander seeds can germinate for three to six years.
Tip: Coriander seeds, and those of other umbellifer plants (Apiaceae), join together in pairs. As such, a single coriander seed is actually hemispherical. Commercially available seeds are separated by machine, but they can also be sown together.
Coriander companion planting
Plants neighbouring coriander benefit from the herb in two ways: coriander keeps aphids (Aphioideae) and cabbage white butterflies (Pieris) away, and attracts pollinating insects such as hoverflies (Syrphidae).
Cilantro is an ideal plant partner for cucumber (Cucumis sativus) and beetroot (Beta vulgaris) as well as numerous herbs such as camomile (Matricaria recutita), borage (Borago officinalis) or basil (Ocimum basilicum). Closely related vegetables, such as fennel (Foeniculum vulgare), carrot (Daucus carota), and celery (Apium graveolens), are not suitable for companion planting. Diseases and pests such as the carrot fly (Psila rosae) spread quickly when umbellifers are planted next to one another.
From planting to harvesting, coriander care is particularly important. Why not have a read of our article to find out more about watering and fertilising this aromatic herb.