Judicious use of water is possibly the most important single factor in the production of the best gladiolus spikes. A gladiolus crop must not be allowed to suffer from water stress especially when spikes are emerging. Regular irrigation at an interval of 7 to 10 days depending upon the weather is necessary. Over watering should be avoided. Irrigation should be withheld at least 4-6 weeks before lifting of corms.
After the corms have sprouted well, watering should be done, if necessary. When the shoots are about 20 cm high they are covered by heaping the soil up to a height of10 to 15 cm. Earthing up is essential after 6-8 weeks of planting corms, or before the emergence of the spike. This enables the plants to grow erect despite high winds and rains and suppresses weed growth. Earthing up the soil is a must in case of light soils. These plants need staking for its satisfactory growth and if not staked may fall or break by high wind velocity.
In cases where the spikes grow longer or stems are not strong enough to bear the lodging or mild stroke of wind, they are supported with about 1.5 meters strong stakes. Strings instead of stakes may be used at the time of the appearance of the spikes. Strings are stretched between the stakes along the row to provide easy and adequate support. Staking is done when the plant attains the height of 15 cm in order to provide shelter from the wind.
Curing of Spike (Harvesting)
After planting the corms, gladioli comes into bloom in two to three months, depending upon the species and variety. Early start flowering within 80 – 90 days, while late varieties start flowering within 100-145 days after planting. The flower spike should be cut as close to the base as possible with a sharp knife or scissors after the first floret on the spike has opened. Later on, the other flower buds i.e. florets on the same spike will open in a sequence, slowly starting from below and continuing upward when placed in water.
While harvesting or cutting of the spike, care should be taken that at least four to six basal leaves should be retained on the plant to ensure proper development of corms and cormels. This is vital for the new corms to have good flowers in the following year. For the internal market, flower spikes are cut when 1-2 lower most florets on the spike have opened and for the external market when the colour has fully developed in mature unopened buds. Immediately after cutting, the spike should be immersed (up to 15 cm from base) in a bucket containing water.
The various aspects of quality parameters of gladiolus cut flowers are their keeping quality, straight strong stems free from side shoots, uniformly spread florets with a specified number per spike, turgid florets facing in one direction, colour, freshness, foliage with proper length and free from damage, dust and spray residues, absence of insects, disease and bruising injury.
Gladiolus spikes are generally harvested with relatively few florets showing colour. Vase-life of gladiolus spikes varies from 5-10 days, depending on the cultivar and room temperature. About 2.5 cm long basal ends of the spikes should be cut off and the spikes placed in an acidic solution having pH between 3-3.5 to increase the shelf life. Spikes can also be kept in floral preservatives containing sucrose,8- HQC etc for enhancing the vase life.
- Central Coastal Agricultural Research Institute, Ela, Old Goa, Goa