METHODS FOR SHADING THE TEA BUSHES DURING CULTIVATION

The straw canopy

The straw canopy [本簾被覆; honzu hifuku] is mainly used for the cultivation of shade grown tea bushes used to produce gyokuro and tencha. On top of a shelf-like structure traditionally fashioned out of wood – but contemporarily for ease-of-labor reasons also to be found in stone – a layer of bamboo-reed blinds supporting an additional layer of dispersed straw is used to intercept the sunlight. This method is considered to be the oldest and most traditional way for shading the bushes.

When in early spring the tea garden gives sight of one or two new buds beginning to sprout, the whole garden is first covered with a bamboo-reed screen [葦簾; yoshizu]. This blocks on average 55 to 60% of sunlight. Successively, after approximately 7 to 10 days of initial shading, a wealthy amount of rice straw [稲藁; inawara] is dispersed on top of the reed blinds, evenly layered at a  thickness of approximately 600-700kg per 10 ares of surface. This marks the beginning of the final half of the shading process during which the bushes again remain shrouded in darkness, protected from sunlight to escape possible photosynthesis, for on average 10 more days. During this conclusive stage the amount of sunlight that is prohibited from reaching the vulnerable tea leaf amounts to 95-98%, sheltering the tea bushes in almost ultimate darkness.

The cheesecloth canopy for shade grown tea

In order to reduce the labor intensity which is demanded of the producer when employing reed-blinds and straw covering, the cheesecloth canopy [寒冷紗; kanreisha] uses a black cheesecloth application made of synthetic fibers. Since there are different fibers available on the market with varying opacity, the producer is enabled to regulate the obscurity of his shade grown tea garden more effectively as compared to the uneven darkness that is often the case with manual straw-covering practices. These cheesecloth applications are used in several ways of which I will explain the three most commonly used methods below.

The dual-layered cheesecloth canopy

The dual-layered cheesecloth canopy [棚型二段被覆; tanagata nidan hifuku] is in similarity to the straw canopy mainly employed for the cultivation of gyokuro and tencha. Its construction is in fact a simplification of the straw canopy, formed on a similar shelf-like construction of metal bars. Extended from the metal bars run two layers of wire, which support the cheesecloth curtains used to cover the shade grown tea bushes. In contradiction to the straw canopy which has to be built-up for use and broken down after each harvest season, the cheesecloth canopy may remain in place whole year through. Taking in account that the single action of opening or closing the curtains is what it takes to manage the opacity in the tea garden, this method evidently allows the manufacturer to tend to his garden with greater flexibility and accuracy. Moreover, since the canopy remains in position throughout the year, it becomes possible to use its benefits for other purposes, for example to regulate the temperature in the tea garden by means of protecting the tea bushes from frostbite and cold, as well.

On the other hand, the synthetic fibers and steel poles of this structure are no match for the romantic image of the straw canopy. But that is far from all that this construction is surpassed in by its traditional counterpart. The straw canopy uses natural materials that allow the tea garden to breathe. In addition, the aroma of the straw becomes present in the air that the tea leaf absorbs, adding to the flavor of that tea a unique trait that can only be obtained under a straw canopy. And, when it rains, it is believed that the raindrops that have managed their way through the thick layer of straw carry with them a small amount of nourishment that the straw has bestowed onto them, which they in turn deliver to the shade grown tea leaf and soil. The straw itself, after it has been used on top of the tea garden is also used as a means of fertilizer. After it has served its primary purpose, the straw is dropped into the tea garden, and scattered out onto the harvester’s paths. This thick layer of straw then regulates the soil temperature of the farm, prohibits (to a certain extent) the growth of weeds and grasses, and, as it decomposes, makes its way into the soil to return as nourishment for next year’s new buds.

To summarize, the synthetic solution reduces a producer’s drudge, and proposes other means of application. On the contrary, the traditional method maintains a natural cycle ensuring that no resources go to waste, and that everything is utilized to its ultimate capacity. In recognition of these traits and benefits, the traditional method is most often used for top-notch competition grade gyokuro and tencha. The synthetic method is then used for the manufacturing of high-grade shade grown teas for the wider marketplace.

The application of the dual-layered cheesecloth canopy is similar to the straw canopy. From the time a first leaf unfolds on the tea bushes, the top-layer curtain is closed over the tea garden, obscuring the farm for 65-70%. In addition, the sides of the farm are also sealed off with a layer of cheesecloth, blocking the sunlight for 70%. After approximately 7 to 10 days, when an additional two leaves have unfurled, the lower curtain with 90% shading capacity is spread out to, in combination with the top layer darken the tea garden for 95-98%. The tea bushes remain shrouded in darkness for an overall period of approximately 20 to 25 days before the fresh leafs and buds are ready for harvest.

The tunnel canopy

The tunnel canopy [トンネル被覆; tonneru hifuku] is most frequently used for the manufacturing of kabusecha. The synthetic-fiber cheesecloth is stretched over bent poles that are positioned with the bend right above the surface of the shade grown plants. Since contemporary tea gardens are commonly formed of rows of tea bushes, this structure is designed to encapsulate one whole row in a tunnel of a single layer of cheesecloth. The shading darkens the interior of the tunnel for 60-75%, and for the manufacturing of kabusecha, this structure is maintained for 7-10 days at the end of the growth cycle of the buds and leaves right before harvest.

However, it can’t be said that this method is a very popular nor frequently used approach. Farmers are often reluctant to deal with the inconvenience of first having to erect a structure of poles, and then to stretch the cheesecloth over it. In fact manufacturers prefer to directly blanket their bushes with a layer of cheesecloth rather than having to concern themselves with this time consuming structure that only provides a comparatively small benefit.

Direct blanketing for shade grown tea

The direct blanketing method [直接被覆; chokusetsu hifuku] is the least time consuming and most economical shading method contemporarily in use for the cultivation of tea. In essence it is an abbreviated form of the tunnel canopy, omitting the poles to create the tunnel, applying the cheesecloth immediately on top of the plants. Each individual row of bushes is shrouded in synthetic material during their growth for varying periods of time that are in accordance with the type of tea the manufacturer wishes to produce.

This method is used for the manufacturing of low-grade gyokuro and tencha, kabusecha, and in recent years even for sencha[1]. For tencha and gyokuro cheesecloth with a more dense opacity is employed to achieve a similar effect as more traditional methods, and is applied for approximately 20 days total. In the case of kabusecha regular cheesecloth is adopted to manipulate the sunlight for approximately 10 days until a sufficient kabuse’ka, blanketing aura, is obtained. When applied to sencha, this term is shortened further.

[1] Sencha is commonly cultivated receiving abundant sunlight. In recent years however, the preference of Japanese consumers is inclining to a favor for a more lush umami flavor. Therefore bushes used for the manufacturing of sencha now too have become subject to shading practices in order to enhance the tea’s sweetness and to obscure its bitter flavors.