LILIUM AGRONOMY PRACTICE

Introduction

Lilium is one of the most important bulbous flower, belongs to Liliaceae family, commercially grown in India for cut flowers. Recently, this crop has become popular in many states in India.

Lilies have a very good demand in the flower market as cut flower and pot plants. Out of the different types of lilies, Oriental and Asiatic hybrid lilies and Asiatic hybrid lilies and to some extent the Easter and tiger lilies are the most popular ones. All these lilies are excellent cut flowers. The popularity of these lilies is gradually increasing in India. Some varieties resistant to leaf scorch should preferably be selected for commercial cultivation.

Soil and Climate

Soil with good texture and proper drainage should be preferred. The soil should be light and porous but rich in organic matter. Lilies are sensitive to high concentration of salt which adversely affects the plant growth. The soil used for cultivation of lilies, has good structure particularly the top layers and is also kept well drained during the entire growing period. Maintaining the correct pH of the soil plays a major role in the root development & uptake of nutrients. It is advisable to maintain a pH of6 to 7 for the Asiatic & longiflorum hybrid groups and a pH of 5.5 to 6.5 for the oriental hybrids.

For good plant growth and quality flower production. The night temperature should be around 10-15®C and the day temperature should be 20-25°C. Higher temperature will produce a dwarf crop with less number of flower buds per stem. The plant should not be grown under direct sunlight. In summer months, due to high light intensity, the plants become stunted in growth. A shading screen with 50-75% shade will be beneficial.

Sowing/Planting

As a thumb rule, the bigger the bulbs, more is the stem length and the number of flower per stem. Bulbs less than 10/12 cm in circumference should not be used for flower production In Oriental hybrid lilies, bigger bulbs(as big as 22/24 cm) should be planted as compared to the Asiatic lilies.

Planting density

Planting depth

It is important, that the bulbs are healthy and should have well formed and healthy roots before planting because the water and nutrient absorption during the first three weeks is dependent on these roots. When the shoot emerges the so called stem roots start to develop on the stem just above the bulb. These stem roots instead of bulb roots will soon start supplying water and nutrients to the plant. In order to get excellent quality flowers, the stem roots should be allowed to develop properly. The depth of planting should be 10 – 12 cm winter.

Fertigation

Since lilium is a bulbous crop, most of its nutrients are already present in the bulb itself. Lilium is a very salt sensitive crop and therefore one should take care with applying fertilizers. Especially in the first three weeks when the rooting takes place, no additional fertilizers are required. Good root development is important at this stage. It is however advisable to apply 12:61:00@ 2kg/100m2 at least one week before plantation. Three weeks after plantation: – Calcium Nitrate @ 1 kg/100m2
Six week after plantation : – Potassium nitrate@ 1 kg/100m2

If plants are not strong enough during growing period due to Nitrogen deficiency then a top dressing of Ammonium Nitrate@ 1 kg/100 m2 can be applied up to three weeks before harvesting.

Irrigation

Irrigation is one of the most important factors that promote growth in the cultivation of lilies. Soil is watered before planting the bulbs. Water liberally a few times after planting the bulbs so that the soil properly adheres to the bulbs and roots. Since the stem roots develop in the top soil, it is essential that this top (30cm) soil should be kept continuously moist. However, there should not be any water stagnation. During the dry spell, the water consumption may be as high as 10 litres/m2 per day.

Staking

Staking is one of the important operation in lilly cultivation and it is essential to keep the plants erect. The most practical way to support the crop is by using netting which should be gradually raised as the plants grow in height so as to get long stems during harvest.

Harvesting

Flowers are ready for harvesting between 90-120 days after planting. As soon as first bud shows distinct colouration, the lilies should be harvested. If this is done at a premature stage, the buds will not develop properly. Cutting too late i.e. when the bulbs have opened fully will cause damage to the flowers during transit. Cut stems should be placed in cold water immediately after harvesting if necessity arise the flowers can be stored at 2-5°C for a week or so. Sucrose 5% + HQS 200 ppm significantly increases the vase life of the flowers.

Grading

After Harvesting the lilies are usually sorted by number of flower buds per stem and length of the stem. The leaves from the bottom 10-15 cm of the stem should be removed this still improves the keeping quality of the flowers.

Nutrient deficiency

1) Iron (Fe):
Symptoms:

The leaf tissue between the veins of young leaves becomes yellowish-green, particularly in plants with rapid growth. The greater the iron deficiency the more yellow plant will become.

Control:

• Soil should be well drained with low pH level
• Chelated- Fe should be applied 2-3 gm/m2 before planting & maximum 2 gm per m2 after planting.

2) Nitrogen (N):
Symptoms:

The whole leaf becomes lighter in colour & this is often more noticeable when plants are about to bloom. The plant often seems rather slight in appearance. Soil with a low nitrogen level produce a crop with stems which are lighter in weight & have less flower buds. The foliage in the vase will turn yellow more quickly.

Control:

• Always apply sufficient quantities of nitrogen, preferably based on the results of soil sample.
• If the nitrogen deficiency is diagnosed during cultivation apply an additional rapid action nitrogen fertilizer. However, bear the risk of leaf scorch in mind during this procedure & make sure the crop is always washed off thoroughly.

Abnormalities

Leaf Scorch:

Leaf scorch occurs when there is a disturbance in the balance between absorption & evaporation of water. This is the result of inadequate absorption or evaporation which causes a calcium deficiency in the cells of the youngest leaves. Cells are destroyed & die. A sudden change in the relative humidity inside the greenhouse can affect this process related to poor root system & high salt level in the soil. Large bulbs are more susceptible than smaller one.

Management:

• Disease & pest which could damage the roots should be controlled effectively.
• Soil should be moistened before planting.
• It is better not to use susceptible varieties but if this cannot be avoided do not use a larger Bulbs as these are extra sensitive.
• Plant bulbs with a good root system.
• Plant to an adequate depth i.e. allow 6-10cm of soil on top of the bulb.
• Prevent large differences in greenhouse temperature & air humidity levels during period of increased susceptibility. Try to maintain RH level of approx. 75%.
• Rapid growth must be prevented.
• Ensure that plants maintain even transpiration & avoid excess transpiration by shading.

Virus diseases

Lilies are infected by different types of virus viz. Lily Symptomless Virus, Cucumber Mosaic Virus, Tulip Colour Breaking Virus etc.,. The plants raised from virus infected bulbs become weak in vigor and produces inferior quality flowers. In case of severe infection the plants become stunted and deformed. For production of quality flowers diseases free bulbs should be used.

Insects and pests

APHIDS:

Aphids live only on young leaves particularly at the backside of the leaves .Young buds may also be affected resulting in deformed flowers. Spray Nuvan@ 2ml/liter of water.

THRIPS:

This is also a sucking type of insect. A severe attack will adversely affect the plants growth and flowering. Those flowers will not be accepted in the market. Regular spraying with Monocrotophos @ 2 ml/liter of water will protect the plants from the attack of trips.