Learning how to harvest marijuana at the right time is critically important because it plays a huge part in determining the quality of the weed that is produced and the high that it gives you.
Many growers rush the cannabis harvesting process because they are too eager to try the bud they have worked so hard on growing over the past few months and this can be detrimental to the stash.
As the plant matures it begins to develop and produce more terpenes, these are the aromatic compounds found in most plants that give them their distinctive smell profile. While this is happening the plants trichome heads also begin to create more THC and CBD, which together are the main compounds found in cannabis. THC is the main psychoactive compound that makes you feel ‘high’ and CBD is another compound that is not psychoactive, but is known for its calming and pain relieving effects.
Harvest too soon and the plant wont have had enough time to develop its full smell and taste profile, and it will be noticeably less potent because it will contain less THC & CBD. Harvest too late and the plant has passed the point where it is its most potent and if left too long the taste and smell will also begin to degrade with it.
How do you know when trichomes are ready?
There are a few different methods growers can use to time their cannabis harvesting to perfection. One is by assessing the appearance of the trichomes on the plant as it nears the end of flowering, the other is to assess the appearance of the pistols.
How to harvest marijuana according to trichome colour
To assess whether or not your plants are ready for harvest based on their trichome colour you will need a jewellers loupe or magnifying glass to look through. This method is thought of as the most accurate way to assessing a plants maturity. As cannabis plants mature their trichomes begin to change colour and these small resin glands that cover the buds start out glassy and gradually become more cloudy and eventually change to amber.
What do the different trichome colors mean?
You want to harvest your trichomes ideally when around 85% of them are milky, 10% amber and 5% clear.
Trichome color is glassy
Trichome heads are glassy, this means that the plant is still developing and the buds are not yet ready. Glassy trichomes will not contain as much THC or CBD and so the bud will be much less potent.
Trichome color is cloudy/milky
Trichome heads appear to be cloudy or milky, at this point the bud be most potent because it will contain the highest level of CBD and THC.
Trichome color is amber
Trichome heads begin to turn amber coloured. This indicates that the buds will contain slightly less THC, however the effect will be more of a relaxing and less intense high.
How to harvest marijuana and when to harvest is partly down to preference, if you want your buds to be as potent as possible then you should harvest them when they are mostly cloudy/milky, whereas if you wait a little longer for them to turn amber the high will be less intense and more relaxing.
Other methods to determine marijuana harvest time
Another method that is used to determine the ideal time for cannabis harvesting is to look at the pistols on the plant. Pistols are the name given to the small hairs on the buds of cannabis plants that can be white, brown, orange or yellow.
Pistols are white and stick straight out
This indicates that the plant is not yet ready for harvest.
Pistols are yellowish
This shows that the plant is not ready for harvest.
Pistols have mostly darkened to orange/brown
When around 70 – 90% of the hairs have darkened in colour the buds will have the highest THC levels.
Pistols are almost all darkened to orange/brown
When are around 90 – 100% of the hairs have turned a dark brown/orange colour the plant will slightly less THC and the high will be more relaxing.
Another sign that a cannabis plant is almost ready to be harvested is when the fan leaves begin to turn yellow. When you see this it is a good time to start the flushing process because this is an indicator that the bud will be ready to be harvested within a few days.
As the plant matures and nears the final stage of its life it gradually takes on less water, you will notice that the leaves begin to curl up and dry out, this is usually a sign that the plant is ready to be harvested. However do not confuse this with other issues that can also cause leaves to dry out such as under watering or nutrient deficiency.
All breeders will give you a guide as to how long the flowering time is for that particular strain, this is a rough guide however and so it should be used simultaneously with other methods such as checking the pistols & leaves.
The effects of cannabis harvesting done too late
By harvesting your cannabis plants too late you allow the quality of the bud to degrade the longer you leave it. Over time the THC and CBD content will begin to decrease resulting in weed that is less potent. Some people prefer cannabis that is less potent and there is nothing wrong with leaving the plant until the majority of the trichomes have turned amber. If you harvest when the trichomes are mostly amber the effect that you will get from the high is more of a relaxed calm feeling.
Harvesting a sativa dominant strain too late means that the high will be like that of an Indica and instead of the typical uplifting active high you will feel more laid back and relaxed. However, leave it too much longer beyond this point and the flavour and smell will also start to degrade with the THC and CBD.
For most medical growers it is best to harvest the plant when the trichomes are cloudy/milky because this is the period where the CBD, CBN and THC levels are at their most potent.
Timing your harvests to perfection is all about deciding how you want your high to be, once you have made this decision check what the breeders guidelines are for that particular strain and if on average the plant takes 8-10 weeks to flower from the 8th week onwards I would start checking the buds with a jewellers loupe and looking for those tell-tale signs that she is ready to smoke.
TIP – Harvest sativas earlier – Sativas such as Durban Poison usually take a little longer to flower, but leave them too long and they start to lose their uplifting sativa high. When the plant is nearing the end of its flowering stage check the colour of the trichomes regularly and harvest them when they are cloudy/milky. Once they begin to turn amber the weed will gradually change to having more of a sedative effect.
The effects of marijuana harvesting done too early
If your goal is to yield as much as possible from your cannabis grow and produce good quality weed while doing so then you don’t want to harvest earlier than necessary. By harvesting early not only will the yield be smaller but the bud itself will not be as potent or taste as good. However, there are occasions when an earlier harvest may be necessary. For example poor weather conditions or an issue with your grow room climate can lead to issues such as bud rot. If you get a bad case of bud rot that is isolated to one section of your grow, rather than trying to cure it and risk it spreading the mold to other plants, you can prematurely harvest the plants to salvage what you still have. While this may compromise somewhat on yield and quality, sometimes it is the safest way to save what is left of your grow. You will need to make the decision yourself dependant on how bad the mold is and how close to harvest your plant is.
How to harvest high cbd marijuana strains?
There a few different opinions as to when to cannabis harvesting should begin with high CBD strains. Harvesting too early or too late can be the difference between growing a plant that is usable as medicine to one that is completely useless.
In my experience with high CBD strains it is best to leave the plants a little longer as CBD tends to increase as the trichomes start to age and turn amber in colour. Ideally you should be looking for trichomes that are 20 – 40 cloudy/amber in colour.
High CBD strains – 20 – 40% of the trichomes have turned cloudy/amber.
Cannabis harvesting step by step
Now that you know how to time your cannabis harvesting to perfection, it’s time to learn how to actually harvest your plants, from flushing the plant to trimming it and drying your bud ready to be cured.
Before harvesting marijuana commences, you should begin preparing your plants, this is a three step process.
- Cut out any large fan leaves.
- While you are trimming your plants check for any pests, mold or insect infestations.
- Flush your cannabis plants with plain water to clear out any leftover nutrients. This should be done about 1 – 2 weeks before you begin harvesting marijuana.
Flushing your marijuana plants
Flushing marijuana is only necessary if you are using nutrients. You do not need to flush with organic grows that use no added nutrients.
Flushing is a process whereby you cut out all nutrients and feed the plants with plain pH adjusted water for 1 – 2 weeks, this should be done just prior to harvesting marijuana. This process flushes fresh water through the plant, clearing out any of the chemicals that are left over from the nutrients you have been feeding them.
Is flushing necessary?
Many people argue that flushing isn’t important, and while it wont impact the size of the buds or the THC content, it will improve the taste and smell of the buds. Also, some chemicals found in fertilizers are not meant for human consumption and so could be harmful to smoke. It is down to personal preference, but I would prefer to know that what I am smoking is natural and so I choose to flush for 10 – 14 days before harvesting marijuana plants.
Flushing isn’t something that has to be reserved just for when you harvest marijuana. Nutrients can build up in soil and too many nutrients can be bad for your plants. If you suspect that your plants are suffering from too many nutrients you can do a short 5 day flush before going back onto nutrient feed.
Harvesting marijuana step-by-step
Step 1 – Assess the trichomes
To judge when to harvest cannabis plants you need to take a close up look at the trichomes with a magnifying glass or jeweler’s loupe. Look at the colour of the trichomes, once the trichomes are around 75 – 85% amber coloured you are ready to begin
Step 2: Stop watering
Now that your plants are ripe for harvesting you should stop watering them and just leave them under the normal light cycle for 2-3 days. This starts the drying out process before harvesting.
Step 3: Prepare your drying room
Your marijuana plants are almost ready to be harvested so prepare a space for them to dry out. Ideally you need to have a room or tent that you can do this in. I often use the tent that I have used to grow them in but take all of the equipment out.
Ideally your drying conditions should be:
- In a dark room.
- Temperature approx. 20 celsius.
- Humidity approx. 50%
- With good airflow – using something such as a rotating tower fan is ideal for this.
Step 4: Begin harvesting your marijuana plants
What you will need:
- Shears or scissors
- 70% alcohol to clean the scissors (they will become very sticky)
- Plastic surgical gloves
- A drying rack – You can make this yourself with some string or coat hangers.
- A large plastic tray or a clear table
Before starting to put your gloves on and sanitise your scissors, the resin from the plants will get very sticky so remember to keep cleaning your tools as you go.
Depending on how big your plants are, harvesting marijuana typically takes around 1 hour per plant.
Step 5: Cut the branches off
Here is where the proper harvesting begins. Start by cutting off all of the main branches one by one, you may need heavy duty scissors or some garden shears for this as they can grow thick. As you cut each one, pile them onto a plastic tray or clear table.
Step 6: Check the buds and leaves
Now you should be left with a pile of branches of bud and leaves. Check the branches one by one for any pests, mold or fungi. If you do find any, be sure to cut out any infected parts.
Step 7: Take off the fan leaves
Go through the branches that you have cut off one by one and trim off any large fan leaves so that you are left with mostly buds and small sugar leaves on the branches.
Step 8: Break down the branches
The bigger the branches and buds are, the longer they will take to dry out. I find that it speeds up the marijuana harvest process if you break down the branches and separate the smaller twigs off of the large branches so that they dry quicker. Once you have done this you will be left with two piles, one of large branches and buds and the other of the smaller buds on twigs.
Step 9: Dry your bud
Now it is time to dry your buds by hanging them in your pre-prepared drying room. You may need some string or clothes pegs to help you hang all of the branches up.
Make sure the drying room is dark and you have an extractor running to help regulate the humidity level. If they are laying down on a drying rack be sure to turn them regularly so both sides dry out evenly.
Depending on the size of your buds and the humidity of your drying room, drying can take 7-14 days.
Step 10: Trimming
Once your buds have been drying for 7-14 days they should be noticeably smaller and weigh a lot less after the water has evaporated. The last stage of the marijuana harvest process is to separate the buds from the branches and trim off any remaining leaves that you don’t want.
Some people decide to take off all of the sugar leaves so that they are left with just buds, but I prefer to leave most of the tiny sugar leaves on. Partly because it takes time to trim them and also because the leaves are covered in trichomes too, so will get you high if smoked.
Once you have dried out your buds and trimmed them the process is over and it’s time to begin curing your bud. This final step is vital if you want your bud to stay fresh for longer and keep its taste.
Last but not least, it’s time for you to enjoy the fruits of your labour and sample your hard earned marijuana harvest!