All You Need To Know About Harvesting

17 Dec 2020
Getting to the final few weeks of the flowering cycle is a very exciting time, and all that hard work and effort over the last 10 weeks or more is starting to pay off. All you need to do now is make sure you flush properly and harvest at the right time. Below is explained all you need to know about the final stages of your Cannabis plant’s life cycle, the right time to chop, mistakes to avoid and many other things that will help you produce the best quality flower.

What To Know

Harvesting Cannabis plants takes practice and there are certain traits to look out for. In the old days, many growers would chop on the day stated by the seed packet, or based on how orange and mature the pistils had become. With a modern day awareness, as growers we are able to break down the harvest window and simplify what to look out for.

The Signs To Look For:

1) Trichome Maturity

The first thing you should base your predictions on are the maturity of the trichomes. Ultimately it is these that contain all the essential oils, ranging from terpenes to cannabinoids. The very best way to do this is to take a sample of flower and place it under a magnifying scope. Once you have done this several times and are happy with not only the size of the resin glands, now you need to pay attention to the colour of the trichome.


Trichomes will change colour from clear to cloudy grey, to light yellow and finally a darker amber bordering on red. Each colour will represent a different type of effect meaning the more clear the resin head, the more cerebral the effects will be. Alternatively harvesting your plants with the majority amber colour will result in a much more sedative effect. 

2) Bud Development

A key skill to becoming a good grower is having patience with your flowering plants, and identifying the peak swelling of the calyx. I have personally witnessed growers who have to harvest their flowering room at the same time, causing early finishing cultivars to be picked late diminishing terpene profiles, and late blooming cultivars to be harvested early.

Try to ignore the flowering time suggested by the breeder, and wait until the calyx are as stacked and thick as possible. Some strains will naturally form golf balls at every internode that are hard to squeeze, and others may take on a more elongated sativa dominant. Either way it is better to pick later than early, and be sure to use trichome maturity to help determine the ideal window.

Timing The Flush

Flushing refers to the amount of time a grower spent feeding only plain water for the final 2 weeks of 12/12. It often indicates how clean a flower will taste and the smoothness associated when smoked. There are actually 2 main reasons why we flush growing mediums prior to harvesting.

Using plain water for 14 days will encourage the plants to use up all of its internal nutrient reserve that may have built up over the 10 weeks or more. Some growers will even flush for 21 days, and although there is the misconception you are not slamming the plants with nutrients when they most need it, you are actually encouraging it to push for the final stages. This cleansing process will result in your Cannabis plants showing deficiencies and displaying what is referred to as seasonal colours.


Plain water or water with enzymes will clean the growing medium by dissolving any left over minerals that have accumulated inside the pots and around the root zone. Allowing a 2-3 week period to wash out the grow medium will ensure you have a super clean crop. It is a combination of cleaning the medium and forcing the plants to use their internal reserves that will produce the best looking, smelling and tasting buds possible.

What To Avoid

  • Make sure you do not harvest your plants early on, no matter how tempted you may become. If you are unsure, then wait another week and do the simple trichome and bud development tests before making your final choice.
  • Make sure that the contaminated flower is cut away from the plant and disposed of. Infected buds that have become prevalent with mould or mildew have no use and cannot be salvaged even for extracts.
  • Avoid harvesting little undeveloped buds and just throw these into a bag for making either water hash or dry sift with. 
  • Chopping the plants down based on the day the breeder says. Pay attention to all of the different variables mentioned above and become more familiar with your plants that are being grown as different phenotypes will express themselves differently.

The Perfect Dry Room

How you dry your flowers out has a huge impact on how they look, the terpenes, how well it burns and smells when burning and overall experience. Learning the hard way about dry rooms can be an expensive lesson so below are 5 top tips when leaving your crop to dry either wet trimmed or drying out.

  • Aim for 60% relative humidity and do not let the room become too dry or damp.
  • Keep the room temperature as close to 15 degrees celsius as possible. 
  • Allow your plants space to hang and do not let them touch the sides of the walls
  • Never have a fan blowing at the buds and create a light oscillating breeze facing away.
  • Give the plants 14 days to dry for the best quality of flower.