A coriander is an erect annul herb from the family Apiaceae. The leaves are variable in shape, broad and are found the base of the plant.
The flowers of coriander are found in groups. Each flower is white or pale pink in colour. The petals of each flower face away from the center of the group.
The fruit of this plant is oval-shaped and yellow-brown in colour and it has two seeds.
Coriander grows only in one season and reaches up to a length of about 50 cm.
Preparation of the soil
It grows in soil with sufficient drainage of soil. It mostly grows up in sandy-loam, loamy and clayey soils. Corianders usually grow in soils with a pH(Potential of hydrogen ions) range of 6.1-7.8 (mildly acidic-mildly alkanic).
The soil in which coriander grows needs to have 2-3 inches of organic matter or manure on the top soil.
Process of growing coriander
Corianders usually grow in areas in damp conditions with cool springs and hot dry summers with temperatures between 20°C and 30°C.It can grow in slightly cold conditions but the warm conditions will cause it to ‘bolt’ which means to go back to the seed. It grows best when positioned in full Sun.
Coriander plants grow directly from the seeds and should be sown between June to July and from October to November.
The whole coriander seeds do not germinate, thus, they are split into half before sowing them. They need to be transplanted. Transplanting is the process of first growing a seed in a green house and then growing it in the field. Corianders need to grow about 2-3 inches tall when they are planted in the field.
First irrigation is given 2-3 days after sowing.
Thereafter at 10 to 15 days interval depending upon the soil moisture available in the soil.
Controlling pests and nutrient deficiencies in coriander
Leaf hoppers are very common pests that attack on coriander leaves. They are tiny, triangular variable-coloured insects which can be found on the other side of the leaf or on the stem. They suck out the juices from the plant’s leaves and inject stunting micro-organisms into the leaf.
They cause a disease known as the Aster’s disease. The symptoms of this disease are-
It makes the plants grow thin
It also turns the flowers yellow in colour
It makes the plant dry
The leaf hoppers can be controlled by using insecticidal soap spray, neem oil or pyrethrum.
Aphids are common pest which can be found on the underside of the coriander leaves. Aphids suck the juice from the leaves and leave a sticky substance behind.
The symptoms of aphids in a plant are-
Leaves turning yellow, crinkling or curling
Stunted plant growth
Aphids can be controlled by-
Importing ladybugs in the field which feed on aphids
Using organic insecticidal soap
Army worm is another common pest which attacks coriander leaves. It has various colours like black, dark greenish-brown and have dark brown, white and orange stripes. It is about 1.5 inches long and its head is yellowish brown in colour.
They live in a brownish-coloured shell just below the surface of the soil and are easy to see.
The moth of the army worm is about 1 inch long and has a 1.5 inch wing span. It’s each forewing is light brown to tan coloured with a white spot. It lays eggs in rows on the undersides of the leaves of the host plant. It rolls the leaves around its eggs to protect them.
They feed mainly on leaves of plants.
They can be controlled by handpicking them and dropping them in a bucket of warm soapy water.
Bacterial leaf spot
This is a disease caused by bacterium. In this disease, the water-soaked spots between leaf veins enlarge and turn from brown to black. The stems may have elongated dark stems and growing flowers turn yellow or brown.
These bacterium are very hard to control. They can be controlled by-
Planting seeds free from pathogens like bacteria, fungi or virus.
Avoiding overhead irrigation
This disease is also caused by bacteria. In this disease, the water -soaked damaged tissues near the base of petioles become soft, sunken and brown.
This disease can be prevented by-
Planting coriander in well draining soils like clayey, sandy loam or loamy soil
Allowing coriander plants to dry before irrigating again
Avoid harming plants while harvesting to prevent pest harvest development of disease