The optimal growth environment for garlic involves several aspects, including soil, temperature, light, and humidity.

　　I. Soil Conditions

　　Garlic prefers to grow in loose, fertile, well-drained sandy loam. This type of soil is conducive to the growth and development of garlic roots, and also facilitates the formation and enlargement of garlic bulbs. Garlic also has certain requirements for soil pH, with the most suitable pH being between 6.0 and 7.5. It grows poorly in acidic soil, and the root tips may become thick and cease growing. Therefore, soil improvement should be carried out before planting garlic to enhance soil fertility.

　　II. Temperature Conditions

　　Garlic prefers a cool environment, with a suitable growth temperature of 12-26℃. Garlic cloves can germinate at low temperatures of 3-5℃, but germination is relatively slow; at temperatures above 12℃, germination is faster and more uniform. The suitable temperature for seedling growth is 12-16℃. At this time, garlic has strong cold resistance and can withstand short periods of low temperature. However, when the temperature rises above 26℃, the stems and leaves of garlic will begin to wither, the roots will die, and the garlic will Enter dormancy. Therefore, during the growth period of garlic, the temperature should be properly controlled to avoid the adverse effects of high temperature on garlic growth.

　　III. Light Conditions

　　Garlic is a long-day plant and requires a long period of sunlight to meet its normal growth and development. If the sunlight is insufficient, the garlic bulbs will not be able to form and enlarge normally. Therefore, during the growth period of garlic, sufficient sunlight should be ensured every day. Specifically, northern varieties have stricter requirements for the number of daylight hours, generally requiring more than 14 hours; while southern varieties have relatively lower light requirements, generally requiring around 13 hours.

　　IV. Humidity Conditions

　　Garlic also has relatively high requirements for soil moisture. Garlic's need for soil moisture varies during different growth stages. During the germination stage, higher soil moisture is required to promote root and sprout development; during the seedling stage, excessive moisture should be avoided to prevent excessive growth of seedlings, but the soil should be kept moderately moist to promote the longitudinal growth of the roots; during the bulb and flower bud differentiation stage, higher soil moisture is also required; while during the bulb enlargement stage, soil moisture should be appropriately reduced to avoid rot and blackening of the bulb skin. In general, the soil should be kept moist but not waterlogged during garlic growth.

　　The optimal growth environment for garlic includes loose and fertile sandy loam, a suitable temperature range (12-26℃), sufficient sunlight, and moderate soil moisture. When planting garlic, these conditions should be properly controlled to ensure normal growth and high-quality yield.