The Relationship Between Greenness of Tea Leaves and Fertilizer | HOJO Online Speciality Tea Shop

For both tea and vegetables, there’s a common misconception that a deeper green colour indicates better quality and greater health benefits. However, this isn’t always the case.

Natural plants often have a yellowish-green hue rather than a vibrant green.

If you observe wild plants in grasslands or along roadsides during spring, you’ll notice that they typically display a surprising yellow-green colour. Conversely, vegetables grown in cultivated fields exhibit a much richer, deeper green shade, making the field boundaries clearly visible even from a distance. When fertilizer is applied to grass in meadows, the previously yellowish-green vegetation transforms into a lush green, with the fertilized areas noticeably standing out and experiencing significant growth. Similarly, houseplants tend to appear yellowish-green when lacking nutrients, but they turn into a deep green when provided with adequate fertilization.

Tea cultivated without the use of fertilizers often results in smaller leaves with a yellowish-green tint.

This phenomenon is particularly evident in certain regions, such as remote mountain villages in Yunnan Province, where tea bushes are tended to in traditional ways. For the minority communities inhabiting these areas, tea isn’t something they actively cultivate; rather, it naturally thrives in the mountainous terrain. They only clear the undergrowth during the tea-picking season. Throughout the year, no pesticides, fertilizers, or pruning are applied, adhering to a farming method that can be described as simply leaving the tea plants untouched. In Japan, this method is known as natural farming, while in China, it’s referred to as “Sheng-tai Cha”. Tea produced through such methods typically exhibits smaller leaves and a yellow-green coloration.
This agricultural style has been practiced in Yunnan Province for several centuries; however, in recent years, such traditional tea gardens have been on the decline. As these regions gain fame, the demand for their teas surges, consequently driving up prices. In an effort to enhance income, farmers often resort to applying fertilizers, resulting in tea leaves taking on a deeper green hue. Additionally, this practice leads to an increase in leaf size and growth rate, resulting in a significant boost in harvest yield.

Tea gardens maintained in a natural, unattended manner without the use of fertilizers.

Naturally Cultivated Spinach Tends to Have a Yellowish-Green Color

Have you ever seen naturally cultivated spinach? When we think of spinach, we often picture a deep green colour, but spinach cultivated without nitrogen fertilizers surprisingly appears yellow-green. Specifically, we are referring to spinach grown in fields where fertilizers have not been used for over 7-8 years, allowing the soil to completely recover from the effects of fertilizers.
While I don’t have photos to share of naturally cultivated spinach, you can find various images by searching on platforms like Google using keywords such as “spinach” + “natural cultivation” or “spinach” + “no fertilizer.” Natural spinach might be overlooked due to its somewhat yellowish appearance, but its taste is incredibly rich with a sweet aftertaste, making it a memorable culinary experience once you try it.

Plants That Grow Rapidly Often Exhibit a Deep Green Colour

Plants in the natural environment are typically deficient in nitrogen, so when nitrogen fertilizers are added, they quickly absorb nitrogen. This rapid absorption prompts the plants to grow rapidly as well. Consequently, they synthesize chlorophyll, the green pigment responsible for photosynthesis, in abundance, turning into efficient photosynthetic factories. As a result, plants enriched with nitrogen exhibit a very deep green colour, and their leaf surfaces expand to efficiently absorb more light.

The image below shows an area that was once a naturally cultivated tea plantation until a few years ago. Due to the growing popularity of the region, it quickly transitioned into a site cultivated with fertilizers. Contrasting with the naturally cultivated tea plantation above, the tea leaves here are larger, darker in colour, and exhibit numerous surface irregularities. It is believed that plants develop surface irregularities on leaves to increase their surface area, facilitating easier absorption of light.

Rapid Growth Often Results in a Lighter Flavor

Fast-growing crops tend to produce less robust flavours naturally. This is comparable to aquaculture fish raised under accelerated growth conditions, where the tea’s rapid growth often yields a lighter flavor profile. Conversely, tea plants that mature at a slower pace develop firmer leaves and impart an exceptionally rich taste. The superior quality of high-mountain or old-growth tree tea is also attributed to this slower growth rate. When selecting tea, I prioritize gardens that have undergone a slower growth process. Conditions such as no fertilization, no pruning, high-altitude cultivation, old-growth trees, a more northerly latitude, and clayey soil contribute to a slower growth rate, resulting in tea of exceptional quality.

Tea produced without the use of fertilizers often exhibits a yellowish tint overall.

The Role of Magnesium in Chlorophyll and Its Impact on Taste

Chlorophyll, the green pigment in plants, contains magnesium within its molecular structure, along with nitrogen. Magnesium is known for its bitter taste. When magnesium interacts with water, it imparts a bitter and astringent flavor. As mentioned earlier, tea cultivated with fertilizers tends to contain higher levels of chlorophyll. During tea processing, when chlorophyll oxidizes, its molecules break down, releasing the magnesium contained within. While this is a hypothesis, it is possible that slightly oxidized green tea from conventional cultivation (fertilizer-based) may become excessively bitter due to the release of magnesium ions during chlorophyll oxidation and decomposition, impacting the tea’s taste.

In summary, a deep green colour typically signifies vigorous plant growth, often promoted by the use of fertilizer, whether organic or chemical. However, if you’re seeking a tea with a lingering aftertaste, richness, and depth of flavor, it becomes essential for tea leaves to display a yellowish-green hue rather than a vibrant green.

There are exceptions, though; for example, tea cultivated in shaded environments, even if it’s naturally farmed, tends to exhibit a deeper green colour. Due to the limited sunlight in shaded conditions, plants synthesize more chlorophyll, enhancing their ability to absorb sunlight efficiently. The photo above depicts naturally cultivated tea, albeit grown in a shaded area.