Crocus bulb, choosing and buying
Crocus is mainly propagated by tunicated corms. Corms selected for planting should be free from cut or marks and from rot or insect damage. Corms are selected on the basis of diameter and their weight. The critical flowering size of corms should have a diameter more than 2.5 cm and weight around 10 gm or more. Selection of best corm is important for production of commercial quality saffron because the number of flower and weight of stigma depends on corm size. For proper rooting and shoot development, corms must receive a 9oc temperature treatment for a minimum of 13 to 20 weeks.
Planting Crocus
The site selected for planting should be sunny, free from disease infection and water stagnation. They require competition free planting positions on a rock garden or on a warm bright dry edge for their long term success.
Before planting Crocus, the soil should be thoroughly ploughed up to depth of 30 cm. Corm should be planted at a depth of 8-10 cm. The ideal distance between plant to plant is 3-6 cm. Planting of corms should be done in upright position. Depth of planting affects corm production. More daughter corms are produced from shallow planted bulbs than from deeply planted ones. Some delicate species which need protection from rain & wind should be grown in pots or tubs. Generally 5-6 corms are used in a 10 cm pots and 7-9 corms can be planted in 12.5 cm pots.
Corms selected for planting should be treated with fungicides like Bavistin @2.0 grams per litre. It is also advisable to remove 2-3 layers of external tunics, previous year root and old flattened corms because they can cause fungal infection.
Crocus - season and cycle
Planting time varies from 2nd week of June to mid September, depends on local climatic conditions. In Crocus sativus flowering occurs in early autumn i.e. from end of September to the middle of November. It takes around 40 days after planting. Maximum development of leaves, root and corms occurs during the winter months i.e. from October- February. At the end of March plants begin to dry up.
Growing period for Crocus
The leaves and roots are produced from September onwards with reabsorption of the mother bulb and production of daughter corms. The new corms begin to form after the autumn blossom and complete their development before the foliage dried out in May. Each mother bulb produces three or four new daughter bulbs in the second year, while the mother bulb decays itself. In third year 1-6 new daughter corms are produced from mother corm of the previous year which also then decays.
Crocus care
Crocus requires light but frequent watering during their active growth and in dry spell. Competition between weeds and crops results in reduction in size of daughter corms and subsequent yield. When the plants begin to dry out in May, cut all the weeds and remove from the field. Weeds can be controlled by manual or by spray of appropriate herbicides.