HOW TO GROW CORIANDER FROM SEED
Coriander is now one of the most common herbs in use today. It is superb at livening up salads and is an essential ingredient in many Asian dishes. Its recent popularity may be due in part to the plants culinary adaptability. This is because both the seeds and the leaves of the coriander plant can used in cooking. The seeds have a slight lemony flavour and are often ground up and used as a spice. The leaves however have a fresh and slightly bitter taste, and these are usually chopped up and added to dishes, soups, breads or used raw as a garnish.
Of course, coriander is easily available in supermarkets. If fact you will generally have a choice of buying it dried, pre-packed freshly cut stems or even living/growing potted plants. Be that as it may, none of these options will give you the quality of flavour that can be produced by growing your own coriander plants. Why? Well dried coriander will always lose flavour during the drying process – this is sadly inevitable. The freshly cut stems are from plants that are grown in highly controlled nursery conditions whose sole aim is to produce a product that fits a size and weight – not a quality of flavour. The same can be said for the pot grown coriander. These plants would have been fed on a computer controlled nutrient drip irrigation system and then placed under light controlled systems to help draw them up to a specific size. You may even find that that they have been subject to plant growth hormones such as gibberellic acid.
While these techniques can show excellent results when growing a plant to a required size, in the quickest possible time, they are not designed to grow a plant with the best possible flavours. However, this can be improved by re-potting supermarket plants into a good quality soil based compost followed by hardening the plants off for a suitable position outside. Just be aware that it may take a few weeks before you end up with a decent tasting plant!
Coriander is easily grown from seed, but because the roots are very sensitive to disturbance they should be grown in pots, modular trays, or better still sown directly outside into their final position. Be aware that transplanting young coriander plants outside into their final position can stress them to a point where they will bolt and go to seed. Of course this is fine if you are growing coriander for its seeds, but not if you are growing coriander for its leaves! Refrain from giving coriander plants additional plant feed such as a weekly liquid fertiliser as this too will also encourage it to bolt.
If you have the protected space available then you can consider sowing coriander at any time of the year so long as average temperatures are not likely to drop below 16 degrees Celsius. This makes coriander ideal for growing indoors so long has you have a sunny windowsill or conservatory as you will need at least 4 hours of bright light per day to maintain healthy growth.
Using a suitable sized pot or container – it will need to be at least 6 inches deep so that the root system can develop – fill it with a good quality multipurpose compost such as John Innes no 1 or 2. You may wish to mix in horticultural grit or perlite to help improve drainage. Sow seeds into holes around ½ inches deep, with each seed 2 inches apart and then lightly cover with some more compost. You can expect the coriander seed to germinate anytime form a few days up to no more than 3 weeks,. From this point on they will need to be regularly watered making sure that the soil never dries out. Just make sure that the young root systems do not become waterlogged through over watering!
If your are planning on starting your coriander seed outside then you can sow them from late April or early May onwards. This is to ensure warm soil temperatures as coriander seed will not germinate in cold weather. You may be able to start earlier that that if they are sown under the protection of a cloche or small poly tunnel.
When direct sowing coriander seed outside choose a sunny, sheltered position, but one that can offer a certain amount of shade during the hottest part of the day in order to keep the foliage soft and flavoursome. If you are growing coriander predominately for its seed then you are better off sowing in full sun without any protection as the hot stressful conditions will trigger flower production far earlier.
Prepare the soil by digging in plenty of organic matter such as well rotted manure or garden compost. When finished, rake over the bed until the top couple of inches turn to a fine tilth then sow each coriander seed ½ inch deep and two inches apart. Cover the seed back over with soil and water in. If you are planting in rows, space each row 1-1/2ft apart. The seed should germinate anytime from a few days up to 3 weeks depending on the weather.
Once the germinated seedlings have reached a height of between 2-3 inches, the weaker plants can be thinned out to one plant for every 4 –5 inches. That way, each plant has enough room to grow to its full size. If you are growing the coriander for its foliage than make sure that you remove any flowering spikes other wise the plants will direct all of their energy into producing flowers and seeds and little or no energy into producing leaves.
You can begin harvesting leave from your coriander plants once they have reached 4 inches in height. Picking the older leaves first will help to encourage further plant growth.
In order to maintain plant vigour, apply a liquid feed to the soil or compost every 2 – 3 weeks during the growing period.
TIP. Sow new batches of coriander seed every three weeks to ensure you have a continual supply during the summer.
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