The two free reports below (no registration or anything) make it look relatively easy, especially if you can keep your water between 65 and 75 F.
Water conditions are the key to mussel growth with the best temperatures between 65 and 75 degree Fahrenheit. The water should be peaceful, well circulated, contain plenty of nutrients, have no pollution, and a depth of 6 to 8 feet (definitely not more than 12 Feet). If the water is too shallow, the temperature will shift too rapidly and the mussels will die. The flow speed should be about 20 Feet per minute. Ideal acid – alkali concentration is 7 to 8 ph. If it is too acidic, the pearls will be small; too much alkali and the pearls come out yellowish. Water visibility should be 6 to 12 Inches.
Generally, planting is done between (March through May) and (September through October) since in the summer the water temperature is too high for just-opened host mussels to survive, while in winter it is too cold for technicians to carry through tricky implant work with their numb fingers. Harvest is usually between October and February; during the fall and winter seasons, mussels produce nacre layers more slowly, resulting in a smoother surface and higher luster.