This research studied the possibility of using atmospheric pressure plasma technology to replace the chemical used in orchids cultivation. By cultivated orchids aged 6 months until growing into a 25 months, it was found that in the case of spraying with chemicals and plasma treated on the leaves and stems of the one orchid for 5 minutes (with frequency of one time per three days), the quality of the orchid leaves has the same luster. For in the case of natural growth, every leaf has spot disease. The creation of a plasma state is a condition in which a temporary chemical reaction is created by an electric filed. The high voltage generated between the electrode can produce unstable atoms or molecules such as O, OH and O3. That can interact with the cell walls of microorganisms. The plasma state is on longer when an electric field is turn off, therefore the charged particles will return to neutral.
From the ability test to inhibit the growth of Bacillus Subtilis (BS) on potato dextrose agar (plate) by culturing under room temperature 25?C - 30?C for 48 hours after treated with plasma jets ( 3 heads type) which produces plasma current at 180 ?A for 5 minutes, it was found that plasma jet inhibited the growth of BS which showed that the growth of BS appeared as points (colony) of bacteria in a smaller number than in the case of untreated with plasma.
However, since the plasma current produced is low at 180 ?A, treated with plasma jet method will take much longer process time (20 times higher) compared to spraying chemical method which takes approximately 15 seconds per one orchid. Therefore, the current process conditions are not suitable for use in large orchids but suitable for raising a small number of orchid breeders for propagated by tissue culture methods.