Growing tea is rather natural gardening experience for gardeners in Hawaii. When I first moved to Hawaii, it made perfect sense to grow tea because of the hilly terrain, rich deep soil, warm climate with no frost, and abundance of rain. Many of these requirements are met for quality tea growing.
Preferred Growing Condition for Tea
Tea grows in tropical to subtropical climate with average temperature 14-16 degree celcius, annual precipitation 1300mm or more. Tea plant is very vulnerable to frost damage. If you get frost in your area, plant should be protected from cold weather and frost damage.
Soil is very important medium for growing most plants, but for tea it is critical to have good soil because the flavor and aroma is greatly influenced. Tea grows in many places in Hawaii, but exceptionally refined taste and aroma of tea is generally found in places with deep weathered soil.
Soil pH is also an important factor. Generally 4.5 - 5 is desired for optimal growth. It can grow in higher pH and some varieties prefer even lower pH than 4.5. Growing environment should make sense to you when you understand the original conditions. Tea evolved in southern mountainous region of China where abundance of rain washes off all the soluble nutrients from the soil along with Calcium which keeps soil pH high.
In the book of Lu Yu "Tea Bible" (or Cha jing in Chinese) written in 760 AD, he describes the soil type and the corresponding grade of tea. This is used for good soil type for many tea types throughout Chinese tea history and even today.
Obtaining your Tea Plants
Now that green tea is very popular, a lot of people want to plant their tea in their yard. You can go around the island and ask people since many people already have in their backyard. If you can find one flourishing in your neighborhood, it is a good sign that the plant is well suited for the environment.
If you really care about what quality you want to get from different varieties, particular varieties of tea should be used.
I found tea plants in many locations, such as local nurseries, plant sale, farmer's market are the easy place to just go and buy. Many of them are not organic and you can tell that the plants are expressing some signs of disease and discomfort.
How to choose a healthy plant
Good plant stock has
1. strong main stem,
2. multiple branches from the base,
3. mature and healthy leaves on branches.
Look for signs of disease. Aphids and leaf rollers are typically found on young leaves. Brown spots, or anthracnose, are also common in some varieties, but healthy growing condition will improve once planted in your yard.
Look at the bottom of the pot for root growth. Healthy plants should have root-to-shoot growth balance in equal proportion. Too much chemical fertilizer will burn the root and you tend to see gorgeous upper body growth, but very small feet.
Generally tea plants for home gardens can be grown organically without much pest problems
Once you obtain your plants, design the site. Flavor and aroma of tea is greatly influenced by what grows around your tea plants. Make sure you don't have any plants with strong smell such as garlic unless the effect is intended.
On a sunny location, dig a hole or trench 16 inches deep by 12 inches wide. Plant them 16-20 inches apart for a hedge. Add organic matter such as compost and manure to improve moisture retention and drainage. Avoid using lime and alkaline amendments. Tea plants are happy with low pH soil. (pH4.5-5).
Once the plants are in the ground, mulch and water well. Keep the soil most for a first few month with frequent watering.
Tea plant does not require much fertilizer once established. You can give fertilizer high in nitrogen and potassium after each harvest as thank you. Check pests and diseases and treat if you see any significant damage. Trim back in the fall. For home gardener this is much like maintaining a hedge.
Wait for first 3 years until the plants are established. Keep in mind that when you start harvesting, you are also taking away their solar panels. They need to produce energy to use for their own growth.
Once the plants are mature and well established, you can pick in the spring, summer and fall, but the best tea is generally in the spring. Pick the stem with leaves. 2 or 3 leaves for better quality, but you can harvest up to 5 leaves for more volume harvest. Note that the flavor get affected by how many leaves on each stem you harvest.
Once you harvest, keep the leaf in cool and shady area until you are ready for processing. Semi-oxidized (or oolong), and fully oxidized (or black) tea go through different processing.
There are also publication on growing tea as well as history of tea in Hawaii and Identification guide for diseases of Tea by University of Hawaii CTAHR.
Small Scale Tea Growing and Processing http://www.ctahr.hawaii.edu/oc/freepubs/pdf/NPH-9.pdf
History of Tea in Hawaii http://www.ctahr.hawaii.edu/oc/freepubs/pdf/tea_04_07.pdf
Identification Guide for Diseases of Tea http://www.ctahr.hawaii.edu/oc/freepubs/pdf/PD-33.pdf