Tea is a major agricultural by-product in China, with national tea income accounting for about 30% of Chinese farmers' earnings. In some regions, tea constitutes the vast majority of income. Understanding where tea grows, its environment, and the conditions for its growth is essential. Generally, high mountains produce good tea, indicating that the growing environment significantly impacts tea quality.
The environment for tea growth involves temperature, soil, sunlight, and rainfall. Tea plants thrive with an annual rainfall of 1000–2000 mm, monthly rainfall exceeding 100 mm during the growing season, and relative humidity of 80–90%. Soil moisture content should be 70–80%. Such conditions are ideal for tea growth. The suitable annual effective accumulated temperature is above 4000°C. If the average temperature exceeds 35°C for several days with drought, branches and shoots may wither.
Sunlight affects tea plants mainly through intensity and quality. Tea plants are shade-tolerant and prefer weak or diffused light. Analysis of chlorophyll absorption spectra shows they absorb the most in the shorter-wavelength blue-violet light range, and diffused light primarily consists of these shorter wavelengths. Thus, tea plants grow better under diffused light. Buds begin to sprout when the average daily temperature stabilizes above 10°C. During the growing season, the monthly average temperature should be above 18°C, ideally 20–27°C.
Under the above conditions, tea grows well, but its taste and quality vary by region. Red soil, yellow soil, sandy soil, and brown forest soil are all suitable for tea growth. The soil structure should have good water retention and permeability, with no hardpan within 1 meter of the surface. The soil must be acidic, with a pH of 4.5–6.5. Tea plants are calcium-averse, requiring limestone content below 0.2% and a groundwater level below 1 meter. Acidic soil is ideal because it provides suitable conditions for tea growth. The root sap of tea plants contains various organic acids, creating an ideal symbiotic environment for root fungi, which improves the plant's nutrition and water conditions.
Some ask if higher mountains always yield better tea. For example, Maojian mountain tea is known for growing at high altitudes. As altitude increases, the air becomes thinner, and atmospheric pressure drops. In such conditions, tea plants' transpiration accelerates. To reduce water loss, the leaves produce resistance compounds to inhibit excessive transpiration, resulting in a notably good taste. While high mountains often produce excellent tea, their yield is low, making genuine high-mountain tea rare in the market. Many products marketed as high-mountain tea are actually from lower hills, sacrificing long-term reputation for short-term profit.
In summary, where tea grows depends on multiple factors, not just one condition. For instance, the Himalayas produce no notable tea. West Lake Longjing tea grows in hilly areas, yet it is often labeled as mountain tea—getting too caught up in details can be confusing. Maojian mountain's altitude is only about 700 meters. The benefits and effects of Dahongpao tea are also linked to soil and climate, demonstrating that tea growth conditions are not solely determined by mountain size.