Cannabis is a seasonal plant that only produces ideal yields when harvested at exactly the right moment. Cultivation conditions and genetics work together to determine when flowering cannabis buds reach their peak, and there are quite a few ways to find out when it’s time to cut and dry your plants. In this guide, learn when to harvest the cannabis you’re growing, and find out what to do with it afterward.
When do you harvest cannabis?
Female cannabis plants are generally ready for harvest 7-10 weeks after the beginning of the flowering phase. Cannabis strains vary significantly in terms of maturation rates, so harvesting one strain at week eight of flowering could mean you’ve waited for too long while another strain might not even be near ready by this point.
Instead of ignorantly cutting down all your cannabis plants at the same time, it’s important to adequately analyze the cannabis you’re growing to determine each strain’s ideal harvestability window. Many breeders provide cultivation guidelines with the strains they develop, and you can also perform potency tests to find out firsthand when your cannabis is at its most harvestable.
How to tell when cannabis is ready for harvest
Veteran cannabis growers can often tell when a cannabis plant has reached its peak by sight alone. For those of us without this sixth sense for weed, there are other options at our disposal:
Consulting grow guides
First, the majority of popular strains have already been grown hundreds of times. Even within strains, cultivation duration can vary slightly from phenotype to phenotype, but these minor variances don’t significantly impact harvested cannabinoid potency. So, if someone has grown a strain that you’re growing, your results will likely mirror theirs almost perfectly.
For rarer strains, you won’t have the luxury of looking up online grow guides. Most amateur cannabis cultivators stick to popular, easy-to-grow strains, though, and the internet is now rife with detailed grow guides for hundreds of cannabis cultivars.
Checking the trichomes and pistils
If you can’t find a grow guide for the particular strain you’re cultivating, you can get a general idea of when your cannabis is ready to harvest based on certain visual cues. With most strains, for instance, the thin, white “hairs” called pistils that extend out of buds will curl up and turn orange as flowering cannabis packs on its final potency. Also, the small oil sacs on buds called trichomes turn cloudy as cannabis matures. You can check the cloudiness of your trichomes using an inexpensive handheld microscope.
Visually inspecting trichomes and pistils is far from a foolproof way to determine if cannabis is ready for harvest, though. Some strains are at their most harvestable when their pistils aren’t quite orange, and trichomes “cloudiness” is an unreliably vague observable variable. The be-all, end-all way to determine if cannabis is ready to harvest is to test it using gas or liquid chromatography.
Testing the potency of your nugs
The only way to be truly exact when determining the exact right moment to harvest your cannabis is to test multiple samples from your plant using chromatography equipment. These days, handheld devices are available that quickly deliver accurate readings of the cannabinoid and terpene potency of cannabis buds.
You can then compare the tested potency of your cannabis to the expected potency range of the strain you’re growing. Even in the absence of existing data, you can determine the ideal harvestability range of any cannabis strain by simply taking consistent readings over time. You might harvest your first crop a little bit past its prime, but with the data you gained, you’ll never make that mistake again.
Harvesting cannabis: indoor vs. outdoor
There are considerable differences between the processes used to determine the harvestability of indoor and outdoor cannabis crops. Indoor cannabis might be ready for harvest at any time, but in most areas of the Northern Hemisphere, outdoor-grown cannabis is only harvestable at a specific time every year.
When to harvest outdoor cannabis
Outdoor-grown cannabis is generally seeded or planted as a seedling in May. The young cannabis plant completes its vegetative cycle by July, at which point it begins producing resinous flowers. Outdoor cannabis flowers reach their maximum potency by mid-October, and they must be harvested soon afterward to avoid seasonal rot.
When to harvest indoor cannabis
Independent from outdoor conditions, indoor cannabis can be cultivated any time of year. Most indoor growers stagger their crops so that many different “batches” of plants are at various stages of the cultivation cycle at any given time. Rather than relying on the cycles of nature to determine ideal harvestability, indoor growers must use the methods listed above to scientifically identify the right moment to cut their cannabis plants from their roots.
How to harvest cannabis: step-by-step
Once you’ve determined your cannabis is ready for harvest, here are the steps you’ll need to take to pick your flowers from the vine and preserve them properly.
1. Confirm your plants are ready to harvest
Before you cut anything, take one last moment to make sure you’re ready to do what you’re doing. Have you properly analyzed and tested your cannabis plants to make sure they’re ready to harvest? Once you cut your buds off from their roots, it will be too late to turn back.
2. Visually inspect your cannabis plants
Now is the time to make sure there’s nothing wrong with your cannabis. At this stage, any mold that may have gotten past your defenses will likely be localized to a single area and easy to cut away. If you hang moldy plants near your other buds, though, mycotoxins can spread through your whole crop.
3. Cut and hang your plants
If you’re sure the cannabis you cultivated has reached maximum potency and won’t compromise anyone’s safety, cut your plants off at the base of the central stalk, and hang them upside down. Cannabis drying environments run the gamut from poorly-ventilated amateur basements to high-tech cryogenic chambers. All you really need to do is make sure your plants are in a dry environment with adequate airflow.
4. Trim & cure your buds
Once they only contain around 10-12% moisture, your cannabis buds can be considered dry. Remove your buds from their stalks at this point, and cut away any excess leaf. Your trimmed buds will then need to go inside sealed mason jars or alternative airtight containers for curing. Glass containers are ideal for curing cannabis, and remember to “burp” or briefly open the tops of your cannabis containers every 24-48 hours throughout the curing process.
Cannabis buds are generally cured and ready to consume within around three weeks. Finally, your hard work has paid off, and your harvested cannabis is ready to vape or smoke.
When to harvest cannabis FAQ
Let’s finish up with some answers to commonly asked cannabis harvesting questions:
How long do you flower cannabis after it has reached full size?
Most strains of cannabis flower for 7-10 weeks after reaching their full vegetative size. Ideal flowering durations vary significantly between strains of cannabis, however, so you’ll need to consult data specific to the strain you’re cultivating to determine exactly how long it should flower before harvest.
When do I stop watering cannabis before harvest?
It’s generally best to stop watering your cannabis plants around three days (72 hours) before harvest. This gives the plants plenty of time to use up any excess water left in their substrate and begin the dehydration process prior to severance from their roots. Allowing cannabis plants to dry out any longer than 72 hours prior to harvest, however, can damage your plants and reduce their potency.
Can you harvest buds at different times?
No, it is best to harvest an entire cannabis plant all at once. Technically, there is nothing wrong with removing buds that have reached peak maturity while leaving others on the vine for a while to benefit from increased light penetration.
In practical terms, however, harvesting buds from the same plant at different times creates more opportunities for stress, infection, and human error. To keep things simple and reduce your chances of harming your cannabis plants, harvest the whole plant all at once at the base.
How do you tell the difference between ripe buds and unripe?
If you’ve spent years around cannabis (especially growing the same strains), you simply “know” when your girls are ready to be cut and hung. The rest of us, however, need to do the following to determine when cannabis is ready to harvest:
- Perform visual inspections
- Consult strain-specific growth cycle information
- Perform lab testing of bud samples
Unless you know cannabis like the back of your hand, don’t leave things up to chance. Test your buds often throughout the maturation process, or better yet, simply leave the delicate task of cultivating cannabis to the experts.