Key Technical Points for Environmental Control in Greenhouse Lily Cultivation

In lily cultivation, besides having high-quality bulbs, strict control of the growing environment according to the requirements of different varieties throughout the entire growth process is also needed to produce lily products with good plant form and high quality. If conditions are not well controlled, it will not only affect the plant form of the lilies, but in severe cases also affect plant growth, and may even prevent normal flowering. The following briefly introduces environmental control during lily cultivation based on the requirements of lily planting.

1. Greenhouse

A good growing environment can ensure the normal growth of lilies. In Dutch lily cultivation, suitable greenhouses are generally available, and they are equipped with various facilities that can maintain suitable climatic conditions (light, temperature, ventilation, air circulation) in the greenhouse. In domestic lily cultivation, however, due to differences in climatic conditions and cultivation levels across regions, greenhouses are also diverse, such as plastic tunnels or multi-span greenhouses, and in many places lilies can also be planted directly in the open air when the climate is suitable. Each region should choose flexibly according to climatic and economic conditions, but if cooling or shading is needed in summer, or cooling or supplemental lighting is needed in winter, caution should be taken, and at least basic heating or cooling facilities and suitable irrigation facilities must be provided.

2. Temperature

To obtain high-quality products, a good root system is very important. During the first 1/3 of the growth cycle, or at least before stem roots emerge, the suitable temperature is 12-13°C, which is beneficial for the growth of lily stem roots. Too low a temperature will unnecessarily prolong the growth cycle, while a temperature higher than 15°C will lead to poor rooting and reduce product quality. Afterward, the temperature is gradually increased, and for lilies of different strains, the suitable temperature for growth also differs.

High temperature and drought will cause lily stems to become shorter and the number of flower buds to decrease; high temperature and high humidity will cause lily stems to become soft and not firm, and leaves to become thinner; low temperature will delay plant growth and lengthen the growing period; drastic changes in temperature and humidity will produce frozen flower buds and increase the rate of split buds and scorched leaves, so throughout the entire process lilies require suitable temperature and humidity to be maintained, with gentle changes. Ventilation can reduce temperature and humidity under conditions of high temperature and high humidity, making plants grow robustly and reducing pests and diseases.

In winter or in cold regions, heating systems are usually used to control the temperature of greenhouses or plastic tunnels. There are many heating methods, such as oil-fired (coal-fired) hot air blowers, hot water pipe heating, steam pipe heating, etc. The power of the heating system needs to be about 220 watts per cubic meter per hour, and each region should choose according to specific conditions.

Using hot water pipe heating gives relatively uniform heat distribution and good operational safety, but pipe heating often raises the temperature relatively slowly.

Using an oil-fired hot air furnace for heating is more convenient, but it must be ensured that the heat distribution of the system can be uniform. In addition, there must be a suitable outlet so that the combustion gases can be discharged freely. If combustion gases accumulate in the greenhouse, ethylene and nitric oxide gases will both cause lily bud drop or poor growth. Heating systems such as pipes or hoses (maximum temperature 40°C) can also be installed under the ground bed.