Garlic can be harvested at different stages of development for specialty markets, but most garlic is harvested when the bulbs are well mature. Harvest occurs after the tops have fallen and are very dry.
High quality garlic bulbs are clean, white (or other colors typical of the variety), and well cured (dried neck and outer skins). The cloves should be firm to the touch. Cloves from mature bulbs should have a high dry weight and soluble solids content (>35% in both cases).
Grades include U.S. No. 1 and unclassified, and are based primarily on external appearance and freedom from defects. Minimum diameter for fresh market is about 4 cm.(1.5 inches).
-1°C to 0°C (30°-32°F) The variety of garlic affects potential storage life, and the recommended conditions for commercial storage depend on the expected storage period. Garlic can be kept in good condition for 1-2 months at ambient temperatures (20°-30°C [68-86°F]) under low relative humidity (<75%). However under these conditions, bulbs will eventually become soft, spongy and shriveled due to water loss. For long-term storage, garlic is best maintained at temperatures of -1°C to 0°C (30°-32°F) with low relative humidity (60-70%). Good airflow is also necessary to prevent any moisture accumulation. Under these conditions garlic can be stored for more than 9 months.
Garlic will eventually lose dormancy, signaled by internal development of the sprout. This occurs most rapidly at intermediate storage temperatures of 5°-18°C (41°-65°F). Garlic odor is easily transferred to other products and should be stored separately. High humidity in the storages will favor mold growth and rooting. Mold growth can also be problematic if the garlic has not been well cured before storing.
Optimum Relative Humidity
60 to 70 %
Rates of Respiration
2 – 6
4 – 12
6 – 18
7 – 15
7 – 13
Fresh peeled cloves
15 – 20
35 – 50
To calculate heat production multiply ml CO 2/kg·hr by 440 to get Btu/ton/day or by 122 to get kcal/metric ton/day.
Rates of Ethylene Production
Garlic produces only very low amounts of ethylene (<0.1 µ/kg·hr)
Responses to Ethylene
Not sensitive to ethylene exposure.
Responses to Controlled Atmospheres(CA)
Atmospheres with high CO2 (5-15%) are beneficial in retarding sprout development and decay during storage at 0-5°C. Low O2 alone (0.5%) did not retard sprout development of ‘California Late’ garlic stored up to 6 months at 0°C. Atmospheres with 15% CO2 may result in some yellow translucent discoloration occurring on some cloves after about 6 months