How and When To Harvest Cannabis – Flush, Harvest, Trim, Dry, Cure

bouque of cannabis flowers

Congratulations on keeping your plant alive this far! Now you get to harvest the flowers. You are here because you have this one (two-part) question: how and when to harvest cannabis? In this article you will learn;

  1. When to harvest
  2. When to start flushing/how to flush
  3. How to harvest (cut off the buds)
  4. How to trim and handle the fresh buds
  5. How to dry the buds
  6. How to cure and store the buds

How to tell if cannabis plants are ready for harvest

All of your hard work from the last couple of months is about to pay off, but you are probably wondering when is a good time to harvest. To answer that correctly you would need to know how far along your plant is in the flowering cycle. Most plants are ready to harvest 90 days from seed or 8 weeks from the vegetative stage.

A better way of telling is by looking at the trichomes on each of the buds using a 30x microscope, or a jewelers loop (to some degree a magnifying glass) When you see the trichomes up close you will notice that it looks like a mushroom, A stem with a bulged head. This is the THC molecule otherwise known as a trichome.

*To see the maturity of trichomes with the naked eye is impossible because it is microscopic matter

There are 3 stages of trichomes that indicate the maturity of the bud/flower.

  • Clear/translucent: The stem and head of the trichomes are both clear. The trichomes are still maturing and are not quite ready to harvest. Harvesting at this point and smoked will give you an all head high. Some people experience headaches when smoking an immature bud.
  • Milky white/opaque: Both the head and stem are milky white. Harvesting when the trichomes are milky white is the optimal time. The trichomes are now “ripe for the picking”. When smoked the effect will be euphoric high that is both a head high and body buzz. This is a great time to harvest but the window is only open for about 5 days after that the trichomes will start to change color to amber.
  • Amber: The head and stem are amber/brownish. trichomes at this stage are overripe and are starting to degrade and get weaker. Harvesting when the bud is more than 50% amber will give you the “couch-lock” heavy high. You know when all you want to do is sleep.

Depending on the color of the trichomes, it will determine what effect you will get from inhaling or ingesting it. I suggest harvesting when the trichomes are 75% milky white with 25% amber. The time frame for this is about 7-10 days after the trichomes start changing color from clear to milky white. Harvesting the bud at this stage will give the best high feeling when smoked. When you start to see the trichomes change color from clear to milky white is when you want to start to flushing the plants.

How to flush cannabis 

To properly flush your plant, you will need to run an excessive amount of PH balanced water though the growing media (ie: Soil/Coco coir) to “flush” out all the built-up salts from nutrients, and any leftover nutrients around the roots.

The reason why you need to flush your plant; when you feed your plant whether it is liquid nutrients, powder, or natural fertilizers there is bound to be an excess of salt in the media and the plant itself since they can store nutrients within its cells. If harvested and dried without flushing first, the chemical compounds of the nutrients will be stuck inside the flowers and it will produce a number of issues when smoked.

  • Gross chemical taste
  • uneven burn
  • dirty black ash

So in order for you to tell the plant to use up all it’s stored nutrients is to starve it and make it consume the last of its energy, flushing the media. How you do this is the same process of feeding the plant, but without the nutrients.

Take about 4 times the water (Lukewarm) that would fit inside of the pot or bucket that the media is in (4 times the volume). PH balance the water to 6.0 to 6.5, and then water the soil just like you would when feeding it.

You will notice a lot of water runoff, and that is good. After running the water through the media, check the pH balance of the runoff water. If it is the same pH as what you are putting into it, then that means you are done flushing for this round. If you are using soil, you will want to flush the soil at least 3 times per week for 2 weeks. If you are growing in Coco coir, you need to do 3 flushes for 1 week (7 days)

If you are using flawless finish from Advanced Nutrients or another final flush solution, you can cut down on flushing by half. (Time and amount of water to be used)

Flawless finish

* Flawless Finish – If you’ve ever coughed your lungs out after ‘enjoying’ your crops, plant pollution may have been the culprit! The same process plants use to grow – absorbing compounds from nutrients, water, and the atmosphere – causes them to build up excess salts and other harsh compounds. If you don’t flush these excesses out before harvest, you compromise final quality. Instead of flushing with plain water, which starves your plants and reduces floral growth and resin, you need Flawless Finish. It uses empty chelates – which are like tiny, powerful vacuum cleaners – to remove excess chemical residues from your growing medium, roots and other plant tissues, including fruits and flowers. The end result is a stellar crop of plants that will be free of at least 85% of the stored materials they held before flushing. Yep, you’ll have the cleanest, sweetest yields possible. 

While flushing cannabis, your plants will react to the lack of food, and the leaves will start to change color. Do not be alarmed as this is the natural way of a plant knowing that it’s about to die. The large fan leaves will begin to change to yellow and begin to fall off. This is caused by the plant using up the stored energy in the large fan leaves to help the growth of the buds (this is the reason why you leave all the fan leaves on to this point). The smaller leaves around the bud are also energy storage for bud growth as well as trichomes growth. Think of this stage as autumn.

PRO TIP: To change the colors even more before harvest; wait two days after the last flush, then turn out the lights and keep it in the dark for 48 hours before you cut them down. This will draw out the purples, the reds, and many other colors depending on the genetics of each strain.

PRO TIP: Turning out the lights for 48 hours prior to harvest stresses the plant, it thinks that it is about to die. Because the flower hasn’t been pollinated yet, she will get more sticky (more trichomes will grow and the oils will secret from the leaves)

PRO TIP: To make harvest day easier start to take off all the large fan leaves during the last flush, it will save time on harvest day.

OK now that we have determined how to tell when it is a good time to harvest and how to flush the chemicals out of the plant, now you need to know how to harvest and trim these buds for drying.

How to harvest cannabis 

Harvesting your plant is going to take a long time. You will want to make sure that when you start to chop branches down, you are going to be able to spend at least 3 hours per plant. When I harvest and trim my four plants it is an all-day event.

Here is a question that I have been asked about harvesting;

Can I harvest the top buds first and then leave the lower branches to grow for a bit longer to help plump them up? Yes, you can, but do note that you have already signaled to the plant that it’s going to die. You have already stressed out the plant, to give it a few more days under the sun will just fill it with stress and won’t really grow those buds much more.

After the 48 hours of darkness, the buds are now ripe enough to harvest. Pretty colors have shown up on the buds and it is time to start cutting down the plant. I start from the bottom and work my way up to the top cutting the largest cola last. The reason I do this is as I am cutting each branch I am making little hooks in the stem where it will be easier to hang up later. Once I cut the branch I will start trimming each bud that is attached to the branch.

How to trim cannabis buds

Trimming is a daunting task that will cramp your hand after a while. Make sure you have the proper tools before you begin.

  • Sharp trimming sheers: They need to strong enough to cut through the thick stem but delicate enough to trim small leaves. It is best to have the shears that come to a sharp point as you will need them to get in the tight areas of the bud to cut off the stems.
  • Rubbing alcohol or Isopropyl alcohol: To clean your tool before starting. It will also help clean the tool afterward.
  • Non powdered latex gloves: must be non-powdered as you don’t want the powder sticking to the buds. You can also trim barehanded with clean hands, but it is easier to collect the resin from gloves than your oily skin
  • Trim bin or table to trim over: You need to have a place where the trichomes that fall off of the bud as your trimming to collect. Also, it is a place where the leaves that you cut off can collect for processing later
  • A comfortable place to sit: you will be sitting for a long time working on trimming those beautiful buds make sure you have somewhere comfortable to work.
  • Paper bags: to put the trim and other leaves in for drying

After cutting off the individual branches, I trim each bud. I start by cutting each of the large leaves off where they connect to the stem, followed by the smaller leaves. When I cut off the leaf, if there is a little stem leftover, I would cut that as close to the stem as I can without cutting the bud.

Making hooks with the branches for easy way to hang up

The reason I cut off that leaf stem is to prevent mold from growing on those sites during drying. After cutting away all the leaves and stems, I cut off all the points of the remaining leaves to help shape the bud.

After trimming, hang up all the buds on the line that you have put up in the space that you are drying in. Hang up each stem filled with buds on the lines with the hooks that we have made from the stems. As for the trimmings that you have collected, put all the leaves and trim into paper bags. Don’t stuff them in the bags, but just enough in it so there will be adequate airflow. Then once a day open the bags and stir the leaves so they can dry evenly, preventing mold from growing. After about 7 days the trim will be dry enough to process into edibles or hash/kief.

Wet trimming vs. dry trimming:

  •  Wet trimming the buds before drying will shorten the drying process to 6-8 days as there are fewer leaves to hold in the moisture. It is easier to trim the wet bud as the leaves are perky.
  • Dry trimming will help keep the taste and aromas within the buds better, however trimming after the buds are dry is difficult because the leaves have curled and are now stuck to the buds. It is a messier job that could cost you pieces of your bud.

I rather trim while it is still fresh I’m not worried about the taste and aroma right now because curing the buds is where the magic happens anyway.

How to dry cannabis

Once all the buds are hung up you will need to control the temperature and relative humidity (RH) in the room. It is best to keep the temp between 18 to 24 degrees Celsius (65-75 degrees Farenhight) and the humidity between 45 – 55 %

Humidity: If levels drop below 30% to 40% the buds will dry too fast trapping the chlorophyll making the bud taste green. If the RH is above 70% then you run the risk of getting mold on your buds. Also, the drying time will be extended.

Temperature: If the temp goes below 18 c drying will slow down and the RH climbs more quickly. If the temp is above 24 c causes the buds to dry too fast and the RH will drop below the ideal 50%

If your buds dry too quickly, the final taste and smell will be like hay or fresh-cut grass. Don’t’ be alarmed if this happens to you, the curing process will bring back the aroma and taste of the buds.

Curing: The Final Stage To Perfecting Your Cannabis

Curing explained: once the bud is dry (7 -10 days) the buds are removed from the branches and placed into glass jars. *Place the buds don’t force them in or pack them in, the buds need room to breathe.* You will screw the lid onto the jar and keep the jar in a cool dark area.

How to cure cannabis

Curing cannabis is like making fine wine. Wine is grape juice that has been fermented in casks and aged to bring out flavors and aromas. This is the same for cannabis. Take the dried buds (that are harsh when smoked at this stage) and put the buds into mason jars for at least 3 weeks. The longer the better. Buds that have cured for 4 months or more are of much better quality than buds that have cured for only 3 weeks.

  • Week One: every day at least twice a day you will remove the lid and let the jar air out for about 15 minutes. Then close the jar.
  • Week Two: every day at least once per day you will open the jar and air out for 15 minutes.
  • Week Three: open the jar and air out for 15 minutes at least once per week. *After the first month if you want to continue to cure in the jars you don’t need to air out the jars anymore as the moisture has all evaporated.

Drying process while curing: the point of curing is to dry out the bud completely. Please note that the flower will lose a lot of weight during the drying process

What happens to the bud in the jar? When you first put the buds into the jar, the outsides of the bud will be dry and slightly crispy. When in the jar and covered, the buds perspire making the outside of the bud moist again. When you burp the jar, meaning when you open the jar to air it out, it releases the excess moisture and slightly dries the outside of the bud. The same process continues until the middle of the bud is completely dry as well as the outside, it creates an environment to dry the bud evenly. By doing this process it will create a product where 100% of the bud is psychoactive.

Curing the buds brings out the aromas and the flavors of the flower. It makes the harshness of the smoke disappear and it becomes very smooth. Your joint will burn clean and even for a longer duration than if smoked directly after drying. You will be able to store the bud for more than a year without the worry of mold.

All your hard work has paid off

You have now harvested the cannabis plant, you have dried the buds, you have cured it all and now you are ready to smoke. Once the paper bags filled with trim is dry go make some sweet black hash. If you are unsure of how to make and press the hash go here to learn more.

If you have any questions or comment please leave a message below in the comment section.

Happy Growing!!!

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