Above - Mel Beard inspects walls of drying flower at 4 Letter Farm's Facility in the Klamath Basin, OR
Harvest season is coming on fast, but are you ready? Long days, late nights, and lots of work - but the moment you've been growing for is here.
No one is ever quite prepared. Odds are you will need more people, more space, and more time; but during this slight lull prior to pulling your plants, do your best to plan. There are many approaches and techniques, but we've gathered the following tips from our years of cannabis cultivation.
Harvest Basics
When and how you harvest should be based off of the following four major factors.
Flower ripeness – if you had your plants in the field by June, generally 25% of your plants will ripen at the end of the first week of September, 40% in the middle, and 35% toward the third week. This equates to about 7-9 weeks in flower. If your plants didn't get in until later just keep in mind - when your plants first ripen you've got a few weeks to catch them all at their prime. Waiting any longer can mean deteriorating plant health and cannabinoid degradation. Harvesting earlier can mean less flower and resin/oil production. We generally start harvesting when over half of the hairs on plants start to turn from white or pink to brown and flowers feel dense or filled in. With our CBD varieties trichomes turn to amber, but in our CBG varieties trichomes remain milky white even after maturity.
Weather conditions – if heavy rains are headed your fields' way and your plants are just about at the peak, start harvesting. Losing a chunk of your crop to mold isn’t worth waiting on a percentage point or two in cannabinoid content. Plants in flower do not like excess moisture, and heavy winds topple wet plants.
People and space – if you are limited on the amount of space and labor you have, we recommend starting harvest earlier than later. This will allow for either staggered drying, or give your workforce a chance to move through the field before plants begin to die off after peak maturity. For drying smokeable flower, empty and refill your drying facilities about every week. How you use your dry room space will also be dependent on your workforce. If you have a large workforce and limited space, cutting off tops is a good option for maximum usage of space. If you are hang drying entire plants, plan on needing about 5,000 sqft of drying space per acre, but it takes significantly less time than cutting off and hanging tops.
Final product – if you are growing for smokeable flower, we recommend starting harvest at the beginning of the harvest window and cutting off the tops of your most developed flowers; and continuing this process until you’ve topped everything in the field. These should be hang dried. For biomass, ideally wait until the middle to end of the peak ripeness window to harvest. If you are in an extremely dry climate, and going for whole plant biomass, some producers cut plants at the base and field dry them. But once again, consider weather factors!
Drying, Curing, and Trimming
The drying and curing process is the final step – and it's important to plan ahead in assembling the pieces of the puzzle. It can be incredibly difficult to track down things like totes, dehumidifiers, and AC's if there are other hemp farmers in your area.
Drying – for the highest quality smokeable flower, we recommend drying plant material in temperatures of around 65-85 degrees. This will keep terpenes and aromatic compounds intact and still allow plants to dry in a timely matter. We use dehumidifiers, air conditioners (and heaters if necessary), and plenty of fans for airflow. We pull material down and put it in totes when stems snap when bent. It is important not to take material down too early as it can lead to mold issues in storage containers. Some growers use large cardboard moving boxes with plastic liners as an inexpensive alternative.
For biomass there are a wide range of options but keep flower below 200 degrees to keep from burning off cannabinoids. Shucking flower off the stem yields the highest quality biomass and is quicker to dry. If your flower is going to be used for full spectrum extracts, treat it similar to smokeable in terms of temperature to keep the material as fragrant as possible.
Curing – we recommend curing plants for cut flower on the stem if possible, and we check our totes frequently to ensure the material isn’t damp after coming out of the dry room. Many people “burp” their totes, essentially opening them up, flipping over the material, and putting the lid back on. It's tedious but a good way to keep tabs on flower moisture. We shuck and trim our flower essentially on demand – when we want to get it to market. This allows for minimum oxidation of the inner flower. Trimmed flower, even under ideal storage, will eventually discolor. Ideally keep your material in temperatures around 50-70 degrees and up to 60% humidity. For biomass, if material is dry, storage temperature is not important.
Trimming – it's another tedious and time consuming job, but hand trimmed flower currently fetches the highest prices on the market. There are services in some areas that will trim your flower for you. Otherwise trim machines can make things go much faster, but can be expensive and not always produce the best results. Do your research.
For some tips on a DIY hemp biomass dryer, check out this great video from Horn Creek Hemp.
