As summer comes to an end, the days are getting shorter and colder. With autumn around the corner, every cannabis cultivator has one thing on their mind: when is the right time to harvest cannabis plants?

Cannabis farmers harvesting plants for sovlentless extraction

There is a variety of factors to consider when planning the harvest of a cannabis crop, especially if the plants are destined for solventless extraction. Both weather and maturity are two important factors that must be considered when scheduling a harvest date.

Fire in, fire out is the priority. The team at Whistler Technologies is here to ensure you can extract the highest amount of high-quality hash out of your crop this season. 

An operator scooping bubble hash onto a tray


Firstly, for many cannabis cultivators, weather is the determining factor for when to harvest their crops.

Fall often brings rain, along with cold weather. This creates the perfect environment for mould, botrytis (bud rot), and other issues to develop.

Outdoor cannabis farm in British Columbia, Canada

As fall progresses, it is important to watch for frost warnings. Water freezing on the bud, or the entire bud freezing and thawing, is not ideal. 

When the water inside the plant cells freezes, the cells burst and die. Once the plant thaws, the wet and dead plant tissue will rot. During cold water extraction, the plant will only degrade further.

The processor is then left with a product that is potentially contaminated with microbes. Even if the product is within safe limits of microbial content, the hash typically will take on a swampy and earthy plant flavour. 

With that being said, the cannabis plant can survive a light frost. Ideally, the plants are covered the night prior using fabric sheets. Plastic sheets should never be used, as they will trap moisture underneath and exacerbate the frost issues.

Once frost warnings are in effect, cannabis farmers should plan their harvest as soon as possible.


Frenchy Cannoli famously speaks about how trichomes are the fruit of the cannabis plant.

This fruit experiences a slow growth during the growing season. Then, it quickly ripens near the end when it becomes time to harvest.

Frenchy believes there is an approximate three-day window to harvest a cannabis plant, to attain the optimal yield and quality for hash. 

As the trichomes mature, an abscission forms between the trichome head and stalk.

When planning a harvest specifically for solventless cannabis extraction, cultivators will want to ensure the majority of the trichomes have reached this stage. This ensures that with a gentle agitation during cold water extraction, trichome heads will fall off with ease.

The best hash is made from trichome heads with minimal plant contaminants. Contaminants could be anything, including bits of plant material, trichome stalks, dust, or dirt. Really, anything that is not a trichome head.

If the process to remove the trichome heads must be excessively rough, contaminants are more likely to come off the biomass during extraction. This results in a lower quality final product

Work with the Experts

Now that you know when to harvest cannabis plants for solventless extraction, check out our other tips on harvesting for solventless extraction.

Whistler Technologies is also available for consulting, on all activities ranging from seed to sale.

Our consulting team has an extensive and comprehensive background, covering everything from facility design, outdoor and indoor cultivation, to solventless extraction at scale and more.

Packaging Solventless Cannabis Rosin Extract

If you need assistance gearing up for harvest season, don’t hesitate to get in touch with us today.