Agriculture / Weights and Measures

All registered commercial industrial hemp crops must be sampled and tested, according to applicable California state regulations, to ensure compliance with the legal thresholds for THC (no more than 0.3%).  Our staff must take official samples from your growing site(s) and send them to an accredited laboratory.

The sampling and testing process is initiated by the grower’s submission of a Pre-Harvest Report form (PHR). The PHR must be filled out and submitted to the SLO County Agricultural Department at least 30 days prior to your intended harvest date.  Incomplete PHRs could delay your sampling date which could lead to your official sample exceeding the legal THC threshold and being subject to possible crop destruction.  PHRs must be emailed to [email protected] or faxed to (805)781-1035.

Prior to submitting your PHR, you must do the following:

• Arrange for transportation and lab analysis with an approved lab.  A list of approved labs serving our county can be provided upon request.  Approved labs are required to have ISO accreditations and the capability to meet the industrial hemp sample regulations. If you are interested to work with a particular lab, please check with us first, to make sure it meets the required accreditations.  In addition, any lab you choose to work with must offer a courier service for transportation of the samples to their respective labs, unless it is a local lab.
• Set up an account with the lab you chose for courier and lab analysis services prior to submitting the PHR. Sampling will not be scheduled until we confirm you have met this requirement. To ensure the integrity of the chain of custody requirements and due to the restrictions currently imposed by private parcel delivery services (e.g. FedEx & UPS), only lab couriers will be allowed to transport these official samples. We expect that there will be additional lab options in the future.

• Within two business days after receiving your completed PHR, our staff will contact you to make an appointment to sample your field(s). You will be billed for staff time and mileage related to sampling activities.  You (or your representative) need to be present at the site during the sampling process.  You have the option to request sampling for an entire site or for portions of a site.  Please remember that you will only be allowed to harvest the portion(s) of the site that were sampled, tested, and determined to have a THC level of 0.3% or less.  If sampling portions of a site are requested, those areas need to be conspicuously marked, and a map displaying the areas must be submitted to the SLO Ag Department.
• Each composite sample for a specific site or area will include five primary samples from at least five random plants. The chain of custody for the collected composite sample(s) will be maintained by Ag Commissioner staff until officially provided to one of the certified lab’s courier service.

When you receive lab results confirming that the THC content is 0.3% or less, you will be allowed to harvest your crop.  You have 30 days to harvest from the sampling date.  For example, if your samples were taken on Aug. 1 and you received lab results on August 10, you have 20 days remaining to complete your harvest.  Harvesting is not allowed until acceptable lab results are received.