Farm cooperative use is the most common way Korean agricultural products are brought to market. Tea is an agricultural product so, quite naturally, tea coops do exist. Many family owned tea farms are all picked and the tea is produced together. Usually, the tea is either hand or machine picked but almost always it is machine produced to maintain consistency of the final product. This method of production is common in Jeju and Boseong producing areas but are quite uncommon in Hadong. The quality of tea produced from coops varies greatly. Examples of these are DAVIDsTEA's Korean Sejak picked in Jeju, almost all Boseong tea, and even Dong Cheon of Hadong.
Company farms/gardens are usually quite small and can involve either machine or hand picked tea leaves. Company farms can be some of the biggest gardens seen in the country but are still quite small compared to the tea fields of China and Japan. They can vary from almost exclusively machine picked and produced tea (such as O'sulloc in Jeju), to completely hand picked and produced teas such as all companies in Hadong (such as Jukro, Joytea, Ssangkye, Woon Sang). Many of these producer farms in Hadong actually have some of the best geographical locations that produce some of the finest hand produced semi-wild tea in Korea.
Larger family farms are actually not that large at all. They are small operations which are almost exclusively hand picked and produced, usually they are of a semi-wild tea plant which is minimally cared for. The difference between these farms and company farms is that these farmers live right off the land. The farms are usually somewhat smaller than the company farms as well. There is large variability in their harvests from year to year. Examples of these are Kim Jong Yeol's Butea and Kim Shin Ho's Samtea. Alternatively, some families in Hadong just keep large semi-wild tea fields but don't produce their own tea. Instead they rent the fields to teamasters who wish to produce their own tea.
Micro-gardens are extraordinarily small productions by locals who have lived with tea and on the land for decades. Often these people have simply been making tea their whole life in this manner. These teas are your only chance for true wild tea in Korea but are very hard to come by even in Korea. These teas rarely get sold outside Korea and are purchased by teamasters within Korea. They rarely hit the shelves for sale to the general public and, if so, often sell for very steep prices. Within the next year or so I imagine these teas will make their way into the Westren market.