Chun'an tea pickers work long hours for fresh tea leaves.

Mingqian tea is known for its tender buds and rich fragrant bouquet, and it's valued for its quality.

However, the temperatures before Qingming are generally low and often unpredictable. The tea shoots are few, and they grow slowly. Few shoots actually meet the exacting standards that are set. They have to be plucked before they harden and mature, but must still be flavorful enough. Thus, Ming- qian tea is pretty rare.

Because of its value, tea producers have not stopped trying to bring forward the normal harvest time of the spring tea, catering to the Chinese tea drinkers' obsession for tasting the first buds of spring.

This commercial opportunity has stimulated experiments, many of them aided by modern technology.

Growing tea in the controlled climate of a greenhouse is no picnic. Many tea producers have tried the method in an attempt to force the bushes to set buds.

But while the greenhouse environment can prompt early budding of the tea, the buds tend to be weak and pale and do not have the aroma needed for a good infusion.

To counter the weaknesses and improve the quality of their early teas, Shao and his companions completed many experiments on temperature, light, humidity and the acidity of soil - all crucial to tea growing.

After five years, they succeeded in bringing forward the harvest by a month. But what mattered most was that their tea buds were fat and vigorous with the requisite bouquet and taste that tea connoisseurs wanted - even after three brews.