Growing Hemp in California

Begin Your Hemp Journey


The balmy, warm climatic conditions in California are ideal for hemp growing which can take place almost all year round. However, the drier climate may mean that farmers may need to irrigate their hemp crops in the drier months in order to meet the seasonal requirements of between 10 and 12 inches of rainfall. A bonus for California farmers is that growing in a drier climate means fewer pesticides, herbicides or fungicides will be necessary giving them the opportunity to grow organic crops to target a more defined market segment. Hemp is adaptive and conducive to growth in most types of soil although loose soil is preferable.

Plant Hardiness Zone(s)

California has multiple plant hardiness zones ranging from 5a to 10b. It is therefore necessary to check the zone for a specific location in the state in order to determine the suitability for growing hemp and the factors that will need to be taken into account.

Thermal Profile

California falls in a South Temperate Thermal Zone which means that it has a mild to warm climate. This warm thermal zone is ideal for planting hemp as are the relative humid conditions that are found in most of the state. However, high humidity can cause problems with mold and fungus and these will need to be managed.

Length of Growing Season

Although California has a temperate climate year round, Summer is still the recommended growing season for hemp. Planting should occur in early May and germination will take place within 3-5 days. The growth cycle for hemp is 110 days. However, it will only start the last phase of maturation when the days are shorter than 12 hours. It is recommended to harvest a crop 8 days after maturation has been reached which should occur in August but is dependent on the planting date.

Average Annual Sunlight

California receives 3,740 hours of sunlight annually with almost 80% of daylight hours being sunny. Hemp is heliotropic which means that it is sun loving and these sunny conditions are therefore optimal for growing hemp in the state.

Average Annual Precipitation

The average annual rainfall in California is 21.44 inches with most taking place in the summer months. This is ideal for hemp which requires between 10 and 12 inches of precipitation during its growing season. Rainfall can mainly be expected in the summer months in California.

Surface Elevation

California has a mean elevation of 2,900 feet ranging from 282 ft below sea level to 14,494 ft above sea level. Although there are plenty of peaks and valleys, elevation in the state should not affect hemp cultivation greatly. Hemp is highly adaptable and extreme cold temperatures are not problematic at higher elevations in the state.

Soil PH

California has an average soil pH level of between 5 and 8.5. which is the ideal range for most types of plants and crops to promote mineral absorption. Hemp prefers a balanced to slightly acidic soil pH of between 6 and 7.

Soil Composition

Soil in California is generally loamy which means that it provides a good mix between sandy and clay. This loose soil is ideal for hemp as it allows for the growth of a long taproot which the plant needs to reach nutrients lying deeper beneath the surface than other types of crops.

Notable Pests

Hemp is specifically prone to mites and aphids which are both problematic insect pests in California – especially red spider mites, gall mites and the woolly beech aphid. Due to the humid conditions in the region, fungus and mold can also be problematic to hemp crops. Pesticides should be a last resort and should only be used before the plants enter the flowering cycle. Pesticides should preferably never be sprayed on the flowering heads.


Click here to read about how we calculate a state’s Hemp Hardiness Score.

Obtaining A Hemp Grower’s License In California

Under federal law, it is illegal to grow hemp anywhere in the United States without first obtaining a grower’s license from the appropriate regulatory body for the state in which the interested party intends to plant the crop. For information on the legal status of hemp in California, as well as a breakdown of the application process, click here.