Abstract
In the Northeast, hemp harvest can take place any time from late August through October or later depending on hemp varieties and weather conditions. Harvest for auto flowering varieties can generally be determined with the use of relative maturity dates for individual varieties, whereas full term or photoperiod sensitive varieties require careful monitoring through the use of visual or aromatic cues. Primarily, harvest date for flower crops is determined by a number of noticeable changes in the physical characteristics of trichomes, bracts, and pistils. The trichomes, known as capitate-stalked resin glands, will begin to form as stalked structures capped with a bulbous head (similar to a small mushroom) on flower surfaces. Depending on the growth, these glands will also begin to turn opaque and eventually amber before degradation. Other flower components such as the bracts of each individual flower will begin to swell, similar to as if flowers were pollenated, and pistils of each flower will begin to turn brown. Once approximately 90% of those pistils have begun browning, in conjunction with these other visual cues, we generally begin to harvest plants.
However, outdoor cultivation can bring various challenges as a result of environmental conditions and pest pressure. A major concern for Northeast growers, and other cooler or erratic weather regions, is the shortening of days and increased risks of frost damage for crops. Risk of frost or crop loss as a result of pest pressure can be major driving factors that will often hasten the necessity for harvest. Harvest date can also impact the chemical composition of flowers impacting cannabinoid and terpene concentrations. Concerns revolving around low cannabinoid concentrations as a result of early harvest are a major concern as crop value can be determined by these concentrations. Additionally, many farmers have concerns surrounding the production of compliant crops and compliance sampling as a result of state and federal regulations in effect. Main concerns often revolve around leaving a crop too long in the field, resulting in THC spikes above action limits as plants are left in the field beyond target harvest date.
Keywords
Vermont, University of Vermont, UVM Extension, Northwest Crops & Soils
Publication Date
6-2023
Recommended Citation
Darby, Heather and Bruce, John, "2022 Hemp Flower Harvest Date" (2023). Northwest Crops & Soils Program. 528.
https://scholarworks.uvm.edu/nwcsp/528